1
|
Almeida D, Sartoretto SC, Calasans-Maia JDA, Ghiraldini B, Bezerra FJB, Granjeiro JM, Calasans-Maia MD. In vivo osseointegration evaluation of implants coated with nanostructured hydroxyapatite in low density bone. PLoS One 2023; 18:e0282067. [PMID: 36812287 PMCID: PMC9946243 DOI: 10.1371/journal.pone.0282067] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2022] [Accepted: 02/07/2023] [Indexed: 02/24/2023] Open
Abstract
OBJECTIVE This in vivo study, aimed to biomechanically, histomorphometrically and histologically evaluate an implant surface coated with nanostructured hydroxyapatite using the wet chemical process (biomimetic deposition of calcium phosphate coating) when compared to a dual acid-etching surface. MATERIAL AND METHODS Ten sheep (2-4 years old) received 20 implants, 10 with nanostructured hydroxyapatite coating (HAnano), and 10 with dual acid-etching surface (DAA). The surfaces were characterized with scanning electron microscopy and energy dispersive spectroscopy; insertion torque values and resonance frequency analysis were measured to evaluate the primary stability of the implants. Bone-implant contact (BIC) and bone area fraction occupancy (BAFo) were evaluated 14 and 28 days after implant installation. RESULTS The HAnano and DAA groups showed no significant difference in insertion torque and resonance frequency analysis. The BIC and BAFo values increased significantly (p<0.05) over the experimental periods in both groups. This event was also observed in BIC value of HAnano group. The HAnano surface showed superior results compared to DAA after 28 days (BAFo, p = 0.007; BIC, p = 0.01). CONCLUSION The results suggest that the HAnano surface favors bone formation when compared to the DAA surface after 28 days in low-density bone in sheep.
Collapse
Affiliation(s)
- Daniel Almeida
- Dentistry School, Universidade Federal Fluminense, Niteroi, RJ, Brazil
| | | | | | - Bruna Ghiraldini
- Dental Research Division, Dentistry School, Universidade Paulista, São Paulo, SP, Brazil
| | | | - Jose Mauro Granjeiro
- Clinical Research Laboratory, Dentistry School, Universidade Federal Fluminense, Niterói, RJ, Brazil
| | | |
Collapse
|
2
|
van Hengel IAJ, Laçin M, Minneboo M, Fratila-Apachitei LE, Apachitei I, Zadpoor AA. The effects of plasma electrolytically oxidized layers containing Sr and Ca on the osteogenic behavior of selective laser melted Ti6Al4V porous implants. MATERIALS SCIENCE & ENGINEERING. C, MATERIALS FOR BIOLOGICAL APPLICATIONS 2021; 124:112074. [PMID: 33947566 DOI: 10.1016/j.msec.2021.112074] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/14/2020] [Revised: 02/26/2021] [Accepted: 03/07/2021] [Indexed: 12/14/2022]
Abstract
Surface biofunctionalization is frequently applied to enhance the functionality and longevity of orthopedic implants. Here, we investigated the osteogenic effects of additively manufactured porous Ti6Al4V implants whose surfaces were biofunctionalized using plasma electrolytic oxidation (PEO) in Ca/P-based electrolytes with or without strontium. Various levels of Sr and Ca were incorporated in the oxide layers by using different current densities and oxidation times. Increasing the current density and oxidation time resulted in thicker titanium oxide layers and enhanced the release of Ca2+ and Sr2+. Biofunctionalization with strontium resulted in enhanced pore density, a thinner TiO2 layer, four-fold reduced release of Ca2+, and mainly anatase phases as compared to implants biofunctionalized in electrolytes containing solely Ca/P species under otherwise similar conditions. Different current densities and oxidation times significantly increased the osteogenic differentiation of MC3T3-E1 cells on implants biofunctionalized with strontium, when the PEO treatment was performed with a current density of 20 A/dm2 for 5 and 10 min as well as for a current density of 40 A/dm2 for 5 min. Therefore, addition of Sr in the PEO electrolyte and control of the PEO processing parameters represent a promising way to optimize the surface morphology and osteogenic activity of future porous AM implants.
Collapse
Affiliation(s)
- I A J van Hengel
- Additive Manufacturing Laboratory, Department of Biomechanical Engineering, Faculty of Mechanical, Maritime, and Materials Engineering, Delft University of Technology, the Netherlands.
| | - M Laçin
- Additive Manufacturing Laboratory, Department of Biomechanical Engineering, Faculty of Mechanical, Maritime, and Materials Engineering, Delft University of Technology, the Netherlands
| | - M Minneboo
- Additive Manufacturing Laboratory, Department of Biomechanical Engineering, Faculty of Mechanical, Maritime, and Materials Engineering, Delft University of Technology, the Netherlands
| | - L E Fratila-Apachitei
- Additive Manufacturing Laboratory, Department of Biomechanical Engineering, Faculty of Mechanical, Maritime, and Materials Engineering, Delft University of Technology, the Netherlands
| | - I Apachitei
- Additive Manufacturing Laboratory, Department of Biomechanical Engineering, Faculty of Mechanical, Maritime, and Materials Engineering, Delft University of Technology, the Netherlands
| | - A A Zadpoor
- Additive Manufacturing Laboratory, Department of Biomechanical Engineering, Faculty of Mechanical, Maritime, and Materials Engineering, Delft University of Technology, the Netherlands
| |
Collapse
|
3
|
Abstract
In this study, we demonstrate that a uniform coating of hydroxyapatite (HAp, Ca10(PO4)6(OH)2) can be electrochemically deposited onto metallic 3D-woven bone scaffolds to enhance their bioactivity. The HAp coatings were deposited onto metallic scaffolds using an electrolyte containing Ca(NO3)2·4H2O, NH4H2PO4, and NaNO3. The deposition potential was varied to maximize the uniformity and adhesion of the coating. Using X-ray diffraction (XRD), Raman spectroscopy, and energy-dispersive spectroscopy (EDS), we found crystallized HAp on the 3D-woven lattice under all deposition potentials, while the −1.5 V mercury sulfate reference electrode potential provided the best local uniformity with a satisfactory deposition rate. The coatings generated under this optimized condition were approximately 5 µm thick and uniform throughout the internal and external sections of the woven lattice. We seeded and cultured both coated and uncoated scaffolds with human adipose-derived stromal/stem cells (ASCs) for 12 h and 4 days. We observed that the HAp coating increased the initial cell seeding efficiency by approximately 20%. Furthermore, after 4 days of culture, ASCs cultured on HAp-coated stainless-steel scaffolds increased by 32% compared to only 17% on the uncoated scaffold. Together, these results suggest that the HAp coating improves cellular adhesion.
Collapse
|
4
|
López-Valverde N, Flores-Fraile J, Ramírez JM, Macedo de Sousa B, Herrero-Hernández S, López-Valverde A. Bioactive Surfaces vs. Conventional Surfaces in Titanium Dental Implants: A Comparative Systematic Review. J Clin Med 2020; 9:jcm9072047. [PMID: 32610687 PMCID: PMC7408888 DOI: 10.3390/jcm9072047] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Revised: 06/17/2020] [Accepted: 06/21/2020] [Indexed: 12/15/2022] Open
Abstract
Animal studies and the scarce clinical trials available that have been conducted suggest that bioactive surfaces on dental implants could improve the osseointegration of such implants. The purpose of this systematic review was to compare the effectiveness of osseointegration of titanium (Ti) dental implants using bioactive surfaces with that of Ti implants using conventional surfaces such as sandblasted large-grit acid-etched (SLA) or similar surfaces. Applying the guidelines of the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) statement, the MEDLINE, PubMed Central and Web of Science databases were searched for scientific articles in April 2020. The keywords used were “dental implants”, “bioactive surfaces”, “biofunctionalized surfaces”, and “osseointegration”, according to the question: “Do bioactive dental implant surfaces have greater osseointegration capacity compared with conventional implant surfaces?” Risk of bias was assessed using the Cochrane Collaboration tool. 128 studies were identified, of which only 30 met the inclusion criteria: 3 clinical trials and 27 animal studies. The average STROBE (STrengthening the Reporting of OBservational studies in Epidemiology) and ARRIVE (Animal Research: Reporting of In Vivo Experiments) scores were 15.13 ± 2.08 and 17.7±1.4, respectively. Implant stability quotient (ISQ) was reported in 3 studies; removal torque test (RTT)—in 1 study; intraoral periapical X-ray and microcomputed tomography radiological evaluation (RE)—in 4 studies; shear force (SF)—in 1 study; bone-to-implant contact (BIC)—in 12 studies; and BIC and bone area (BA) jointly—in 5 studies. All animal studies reported better bone-to-implant contact surface for bioactive surfaces as compared to control implants with a statistical significance of p < 0.05. Regarding the bioactive surfaces investigated, the best results were yielded by the one where mechanical and chemical treatment methods of the Ti surfaces were combined. Hydroxyapatite (HA) and calcium–phosphate (Ca–Ph) were the most frequently used bioactive surfaces. According to the results of this systematic review, certain bioactive surfaces have a positive effect on osseointegration, although certain coating biomolecules seem to influence early peri-implant bone formation. Further and more in-depth research in this field is required to reduce the time needed for osseointegration of dental implants.
Collapse
Affiliation(s)
- Nansi López-Valverde
- Department of Surgery, University of Salamanca, Instituto de Investigación Biomédica de Salamanca (IBSAL), 37007 Salamanca, Spain; (N.L.-V.); (J.F.-F.); (S.H.-H.)
| | - Javier Flores-Fraile
- Department of Surgery, University of Salamanca, Instituto de Investigación Biomédica de Salamanca (IBSAL), 37007 Salamanca, Spain; (N.L.-V.); (J.F.-F.); (S.H.-H.)
| | - Juan Manuel Ramírez
- Department of Morphological Sciences, University of Cordoba, Avenida Menéndez Pidal s/n, 14071 Cordoba, Spain;
| | - Bruno Macedo de Sousa
- Institute for Occlusion and Orofacial Pain Faculty of Medicine, University of Coimbra, Polo I - Edifício Central Rua Larga, 3004-504 Coimbra, Portugal;
| | - Silvia Herrero-Hernández
- Department of Surgery, University of Salamanca, Instituto de Investigación Biomédica de Salamanca (IBSAL), 37007 Salamanca, Spain; (N.L.-V.); (J.F.-F.); (S.H.-H.)
| | - Antonio López-Valverde
- Department of Surgery, University of Salamanca, Instituto de Investigación Biomédica de Salamanca (IBSAL), 37007 Salamanca, Spain; (N.L.-V.); (J.F.-F.); (S.H.-H.)
- Correspondence:
| |
Collapse
|
5
|
Shahmoradi M, Rohanizadeh R, Sonvico F, Ghadiri M, Swain M. Synthesis of stabilized hydroxyapatite nanosuspensions for enamel caries remineralization. Aust Dent J 2018; 63:356-364. [PMID: 29804291 DOI: 10.1111/adj.12624] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/20/2018] [Indexed: 12/11/2022]
Abstract
BACKGROUND The aim of this study was to develop and evaluate a method for synthesizing a stable suspension of hydroxyapatite nanoparticles and to test its efficacy for remineralizing carious enamel lesions. METHODS Hydroxyapatite (HA) particles were synthesized using wet chemistry. Synthesized particles were introduced into a high-pressure homogenizer (5-10 homogenization passes at 15 000 psi) in the presence of different stabilizers. Size and distribution of the resultant particles were determined using dynamic light scattering (DLS). The morphology and composition of the nanoparticles were determined using scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS). Subsequently, artificial lesions were treated with HA nanosuspension plus artificial saliva or a fluoride-containing artificial saliva only. Visual analysis and quantification of the lesion mineral density before and after remineralization were performed using microcomputed tomography. RESULTS DLS and SEM results confirmed the formation of nonagglomerated HA nanoparticles (20-40 nm) following high-pressure homogenization treatment. Quantitative evaluation of the lesions showed that remineralization of the lesion with hydroxyapatite nanosuspension led to a significantly higher level of mineral gain compared to the control group (P < 0.05). CONCLUSION High-pressure homogenization is an effective method for facile preparation of a stable suspension of hydroxyapatite nanoparticles. Treatment of artificial lesions with nonagglomerated spherical HA nanoparticles improves the remineralization of enamel lesion.
Collapse
Affiliation(s)
- M Shahmoradi
- Biomaterials and Bioengineering, Faculty of Dentistry, University of Sydney, Westmead, New South Wales, Australia
| | - R Rohanizadeh
- Faculty of Pharmacy, University of Sydney, Sydney, New South Wales, Australia
| | - F Sonvico
- School of Pharmacy, University Technology Sydney, Sydney, New South Wales, Australia
| | - M Ghadiri
- Woolcock Institute of Medical Research, Sydney, New South Wales, Australia
| | - M Swain
- Biomaterials and Bioengineering, Faculty of Dentistry, University of Sydney, Westmead, New South Wales, Australia
| |
Collapse
|
6
|
Wang Y, Cai X, Huang J, Zhou Y, Jiang T, Wang Y. Bone regeneration in critically sized rat mandible defects through the endochondral pathway using hydroxyapatite-coated 3D-printed Ti6Al4V scaffolds. RSC Adv 2018; 8:31745-31754. [PMID: 35548214 PMCID: PMC9085720 DOI: 10.1039/c8ra06508j] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2018] [Accepted: 09/04/2018] [Indexed: 11/21/2022] Open
Abstract
The endochondral approach has been proved to be a promising pathway in bone tissue engineering. However, whether it is suitable for repairing critically sized mandible defects is unknown. We designed Ti6Al4V scaffolds with a suitable shape and pore size by a 3D-printing selective-laser-melting technique to implement this approach. In order to improve the surface bioactivity of the scaffolds, hydroxyapatite (HA) coatings (HA/L group and HA/H group) of different crystallite size were prepared on the scaffolds via electrochemical deposition. Rat bone mesenchymal stem cells (BMSCs) were seeded onto the scaffolds and chondrogenically differentiated in vitro for 4 weeks and then the scaffolds were implanted into critically sized rat mandible defects for 8 weeks. The bare scaffold and HA coatings were characterized with field emission scanning electron microscopy, water contact angle measurements and X-ray diffractometry. Cell proliferation results showed that the bioactivity of the HA coatings could better improve the growth rate of BMSCs compared with the bare surface. Additionally, safranin O staining showed abundant cartilage matrix and chondrocytes in the HA coated scaffold. Analyses using qPCR detected higher expression of chondrogenic-related gene Col2α1 and vegfα in the HA coated groups, especially in the HA/H group. Together these data demonstrate that the HA coating could improve the chondrogenic differentiation of BMSCs. In vivo, methylene blue staining of histological sections and micro-computed tomography revealed that the HA-coated groups, especially the HA/H group, increased new bone formation via endochondral ossification compared with the control group. Therefore, this strategy provides an alternative method to improve bone formation in mandible defects via the endochondral pathway and the scaffold with larger HA crystals was superior to those with smaller HA crystals. Bone regeneration in critically sized rat mandible defects through the endochondral pathway using hydroxyapatite-coated scaffolds.![]()
Collapse
Affiliation(s)
- Yan Wang
- The State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei-MOST)
- Key Laboratory of Oral Biomedicine Ministry of Education
- School and Hospital of Stomatology
- Wuhan University
- Wuhan 430079
| | - Xinjie Cai
- The State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei-MOST)
- Key Laboratory of Oral Biomedicine Ministry of Education
- School and Hospital of Stomatology
- Wuhan University
- Wuhan 430079
| | - Jing Huang
- The State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei-MOST)
- Key Laboratory of Oral Biomedicine Ministry of Education
- School and Hospital of Stomatology
- Wuhan University
- Wuhan 430079
| | - Yi Zhou
- The State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei-MOST)
- Key Laboratory of Oral Biomedicine Ministry of Education
- School and Hospital of Stomatology
- Wuhan University
- Wuhan 430079
| | - Tao Jiang
- The State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei-MOST)
- Key Laboratory of Oral Biomedicine Ministry of Education
- School and Hospital of Stomatology
- Wuhan University
- Wuhan 430079
| | - Yining Wang
- The State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei-MOST)
- Key Laboratory of Oral Biomedicine Ministry of Education
- School and Hospital of Stomatology
- Wuhan University
- Wuhan 430079
| |
Collapse
|
7
|
Duncan WJ, Greer PFC, Lee MH, Loch C, Gay JHA. Wool-derived keratin hydrogel enhances implant osseointegration in cancellous bone. J Biomed Mater Res B Appl Biomater 2017; 106:2447-2454. [PMID: 29226584 DOI: 10.1002/jbm.b.34047] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2017] [Revised: 09/26/2017] [Accepted: 10/31/2017] [Indexed: 11/11/2022]
Abstract
AIM This study investigated whether a keratin hydrogel derived from wool enhances ossointegration of dental implants, using a cancellous bone model in sheep. METHOD Ten female sheep received one dental implant per hind leg in the distal femoral condyles. Test implants were coated with 1 mL of keratin hydrogel containing sulphonated keratin and hydroxyapatite; control implants remained uncoated; implants were not functionally loaded axially. Biomechanical stability was tested with resonance frequency analysis (RFA) at placement and euthanasia. Animals were sacrificed after 4 weeks and resin-embedded histomorphometry performed. FINDINGS Bone appeared denser and more mature around the keratin-treated test implants. Average % bone-implant contact was significantly increased for the test (58.1 ± 4.6 [SD]%) compared to control implants (34.4 ± 7.5%) (p = 0.01). RFA values were lower for control (76.5 ± 4.2 ISQ) than test implants (80.4 ± 1.4) after 4 weeks (p = 0.04). CONCLUSION the increase in osseointegration found in this model suggests that keratin hydrogel has the potential to enhance the successful osseointegration of dental implants placed into poor quality bone. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 2447-2454, 2018.
Collapse
Affiliation(s)
- Warwick J Duncan
- Sir John Walsh Research Institute, Faculty of Dentistry, University of Otago, Dunedin, 9054, New Zealand
| | - Philippa F C Greer
- Sir John Walsh Research Institute, Faculty of Dentistry, University of Otago, Dunedin, 9054, New Zealand
| | - Min-Ho Lee
- School of Dentistry and Institute of Biodegradable Material, Chonbuk National University, Jeonju, South Korea
| | - Carolina Loch
- Sir John Walsh Research Institute, Faculty of Dentistry, University of Otago, Dunedin, 9054, New Zealand
| | - Jennifer H A Gay
- Sir John Walsh Research Institute, Faculty of Dentistry, University of Otago, Dunedin, 9054, New Zealand
| |
Collapse
|
8
|
Effect of titanium implants with strontium incorporation on bone apposition in animal models: A systematic review and meta-analysis. Sci Rep 2017; 7:15563. [PMID: 29138499 PMCID: PMC5686172 DOI: 10.1038/s41598-017-15488-1] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2017] [Accepted: 10/27/2017] [Indexed: 01/07/2023] Open
Abstract
This systematic review aims to assess the efficacy of titanium (Ti) implant surfaces with or without strontium (Sr) incorporation on osseointegration in animal experimental studies. An electronic search was conducted using databases of PubMed and EMBASE up to November 2016 to identify studies focusing on osseointegration of strontium-modified titanium implants following PRISMA criteria. The primary outcome was the percentage of bone-to-implant contact (BIC) around the implants with or without strontium-modified surface. Of the 1320 studies, 17 studies fulfilling the inclusion criteria were finally included. A random effect meta-analysis was conducted based on BIC in 17 studies, and the results demonstrated considerable heterogeneity (I² = 79%). A sensitivity analysis found that three studies using the same surface modification method were the major source of the heterogeneity. Therefore, exploratory subgroup analysis was performed. Subgroup one including 14 studies showed a standard mean differences (SMD) of 1.42 (95% CI, 1.13-1.71) with no heterogeneity (I² = 0.0%), while subgroup two including the other three studies showed a SMD of 9.49.95% CI, 7.51-11.47) with low heterogeneity (I² = 0.1%). Sr-modified implants in both subgroups showed significantly higher BIC than unmodified implants (P < 0.01). The results showed a statistically significant effect of Sr-modified titanium implant surfaces on osseointegration and bone apposition in animal models.
Collapse
|
9
|
Besinis A, Hadi SD, Le HR, Tredwin C, Handy RD. Antibacterial activity and biofilm inhibition by surface modified titanium alloy medical implants following application of silver, titanium dioxide and hydroxyapatite nanocoatings. Nanotoxicology 2017; 11:327-338. [PMID: 28281851 DOI: 10.1080/17435390.2017.1299890] [Citation(s) in RCA: 90] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
One of the most common causes of implant failure is peri-implantitis, which is caused by bacterial biofilm formation on the surfaces of dental implants. Modification of the surface nanotopography has been suggested to affect bacterial adherence to implants. Silver nanoparticles are also known for their antibacterial properties. In this study, titanium alloy implants were surface modified following silver plating, anodisation and sintering techniques to create a combination of silver, titanium dioxide and hydroxyapatite (HA) nanocoatings. Their antibacterial performance was quantitatively assessed by measuring the growth of Streptococcus sanguinis, proportion of live/dead cells and lactate production by the microbes over 24 h. Application of a dual layered silver-HA nanocoating to the surface of implants successfully inhibited bacterial growth in the surrounding media (100% mortality), whereas the formation of bacterial biofilm on the implant surfaces was reduced by 97.5%. Uncoated controls and titanium dioxide nanocoatings showed no antibacterial effect. Both silver and HA nanocoatings were found to be very stable in biological fluids with material loss, as a result of dissolution, to be less than 0.07% for the silver nanocoatings after 24 h in a modified Krebs-Ringer bicarbonate buffer. No dissolution was detected for the HA nanocoatings. Thus, application of a dual layered silver-HA nanocoating to titanium alloy implants creates a surface with antibiofilm properties without compromising the HA biocompatibility required for successful osseointegration and accelerated bone healing.
Collapse
Affiliation(s)
- A Besinis
- a School of Biological Sciences , University of Plymouth , Plymouth , UK.,b Plymouth University Peninsula Schools of Medicine and Dentistry, University of Plymouth , Plymouth , UK.,c School of Engineering, University of Plymouth , Plymouth , UK
| | - S D Hadi
- a School of Biological Sciences , University of Plymouth , Plymouth , UK
| | - H R Le
- c School of Engineering, University of Plymouth , Plymouth , UK
| | - C Tredwin
- b Plymouth University Peninsula Schools of Medicine and Dentistry, University of Plymouth , Plymouth , UK
| | - R D Handy
- a School of Biological Sciences , University of Plymouth , Plymouth , UK
| |
Collapse
|
10
|
van Hengel IAJ, Riool M, Fratila-Apachitei LE, Witte-Bouma J, Farrell E, Zadpoor AA, Zaat SAJ, Apachitei I. Selective laser melting porous metallic implants with immobilized silver nanoparticles kill and prevent biofilm formation by methicillin-resistant Staphylococcus aureus. Biomaterials 2017. [PMID: 28622569 DOI: 10.1016/j.biomaterials.2017.02.030] [Citation(s) in RCA: 106] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Implant-associated infection and limited longevity are two major challenges that orthopedic devices need to simultaneously address. Additively manufactured porous implants have recently shown tremendous promise in improving bone regeneration and osseointegration, but, as any conventional implant, are threatened by infection. In this study, we therefore used rational design and additive manufacturing in the form of selective laser melting (SLM) to fabricate porous titanium implants with interconnected pores, resulting in a 3.75 times larger surface area than corresponding solid implants. The SLM implants were biofunctionalized by embedding silver nanoparticles in an oxide surface layer grown using plasma electrolytic oxidation (PEO) in Ca/P-based electrolytes. The PEO layer of the SLM implants released silver ions for at least 28 days. X-ray diffraction analysis detected hydroxyapatite on the SLM PEO implants but not on the corresponding solid implants. In vitro and ex vivo assays showed strong antimicrobial activity of these novel SLM PEO silver-releasing implants, without any signs of cytotoxicity. The rationally designed SLM porous implants outperformed solid implants with similar dimensions undergoing the same biofunctionalization treatment. This included four times larger amount of released silver ions, two times larger zone of inhibition, and one additional order of magnitude of reduction in numbers of CFU in an ex vivo mouse infection model.
Collapse
Affiliation(s)
- Ingmar A J van Hengel
- Department of Biomechanical Engineering, Faculty of Mechanical, Maritime, and Materials Engineering, Delft University of Technology (TU Delft), Mekelweg 2, 2628 CD, Delft, The Netherlands; Additive Manufacturing Lab, Faculty of Mechanical, Maritime, and Materials Engineering, Delft University of Technology (TU Delft), Mekelweg 2, 2628 CD, Delft, The Netherlands
| | - Martijn Riool
- Department of Medical Microbiology, Center for Infection and Immunity Amsterdam (CINIMA), Academic Medical Center, University of Amsterdam, Meibergdreef 9, 1105 AZ, Amsterdam, The Netherlands
| | - Lidy E Fratila-Apachitei
- Department of Biomechanical Engineering, Faculty of Mechanical, Maritime, and Materials Engineering, Delft University of Technology (TU Delft), Mekelweg 2, 2628 CD, Delft, The Netherlands; Additive Manufacturing Lab, Faculty of Mechanical, Maritime, and Materials Engineering, Delft University of Technology (TU Delft), Mekelweg 2, 2628 CD, Delft, The Netherlands
| | - Janneke Witte-Bouma
- Department of Oral and Maxillofacial Surgery, Special Dental Care and Orthodontics, Erasmus MC, University Medical Centre, Wytemaweg 80, 3015 CN, Rotterdam, The Netherlands
| | - Eric Farrell
- Department of Oral and Maxillofacial Surgery, Special Dental Care and Orthodontics, Erasmus MC, University Medical Centre, Wytemaweg 80, 3015 CN, Rotterdam, The Netherlands
| | - Amir A Zadpoor
- Department of Biomechanical Engineering, Faculty of Mechanical, Maritime, and Materials Engineering, Delft University of Technology (TU Delft), Mekelweg 2, 2628 CD, Delft, The Netherlands; Additive Manufacturing Lab, Faculty of Mechanical, Maritime, and Materials Engineering, Delft University of Technology (TU Delft), Mekelweg 2, 2628 CD, Delft, The Netherlands
| | - Sebastian A J Zaat
- Department of Medical Microbiology, Center for Infection and Immunity Amsterdam (CINIMA), Academic Medical Center, University of Amsterdam, Meibergdreef 9, 1105 AZ, Amsterdam, The Netherlands
| | - Iulian Apachitei
- Department of Biomechanical Engineering, Faculty of Mechanical, Maritime, and Materials Engineering, Delft University of Technology (TU Delft), Mekelweg 2, 2628 CD, Delft, The Netherlands; Additive Manufacturing Lab, Faculty of Mechanical, Maritime, and Materials Engineering, Delft University of Technology (TU Delft), Mekelweg 2, 2628 CD, Delft, The Netherlands.
| |
Collapse
|
11
|
Dhaliwal JS, Albuquerque RF, Fakhry A, Kaur S, Feine JS. Customized SmartPeg for measurement of resonance frequency of mini dental implants. Int J Implant Dent 2017; 3:4. [PMID: 28150188 PMCID: PMC5289123 DOI: 10.1186/s40729-017-0066-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2016] [Accepted: 01/13/2017] [Indexed: 12/03/2022] Open
Abstract
Background One-piece narrow diameter implants (NDIs) have been recommended as “Single-tooth replacements in the anterior zones, single posterior, multiple-unit fixed dental prosthesis (FDP), edentulous jaws to be rehabilitated with FDP, and edentulous jaws rehabilitation with overdentures in situations with reduced mesiodistal space or reduced ridge width.” (ITI consensus 2013). Since NDIs can be immediately loaded, it is important to be able to carry out stability testing. We developed and validated a customized SmartPeg for this type of implant to measure the Implant Stability Quotient (ISQ). The ISQ of mini dental implants (MDIs) was measured and compared with the stability of standard and in a rabbit model. Objective The aim of the study is to test the feasibility of a customized SmartPeg for resonance frequency measurement of single-piece mini dental implants and to compare primary stability of a standard and the mini dental implant (3M™ESPE™ MDI) in a rabbit model after 6 weeks of healing. Methods Eight New Zealand white rabbits were used for the study. The protocol was approved by the McGill University Animal Ethics Review Board. Sixteen 3M™ESPE™ MDI and equal number of standard implants (Ankylos® Friadent, Dentsply) were inserted into the tibia/femur of the rabbits and compared. Each rabbit randomly received two 3M™ESPE™ MDI and two Ankylos® implants in each leg. ISQ values were measured with the help of an Osstell ISQ device using custom-made SmartPegs for the MDIs and implant-specific SmartPegs™ (Osstell) for the Ankylos®. Measurements were obtained both immediately following implant placement surgery and after a 6-week healing period. Each reading was taken thrice and their average compared using Wilcoxon matched pairs signed-rank tests. Results The median ISQ and interquartile range (IQR) values were 53.3 (8.3) at insertion and 60.5 (5.5) at 6 weeks for the 3M™ESPE™MDI and, respectively, 58.5 (4.75) and 65.5 (9.3) for the Ankylos® implant. These values also indicate that both types of implants achieved primary and secondary stability, and this is supported by histological data. ISQ values of both 3M™ESPE™ MDI and Ankylos® increased significantly from the time of insertion to 6 weeks post-insertion (p < 0.05). Conclusions The new custom-made SmartPeg is suitable for measuring the Implant Stability Quotient of 3M™ESPE™MDIs. The primary stability of 3M™ESPE™MDIs is similar to the primary stability attained by standard implants in the rabbit tibia.
Collapse
Affiliation(s)
- Jagjit Singh Dhaliwal
- Faculty of Dentistry, McGill University, 2001 McGill College Avenue, Suite 500, Montreal, Quebec, H3A 1G1, Canada.,PAPRSB Institute of Health Sciences, Universiti Brunei Darussalam, ᅟ, Brunei Darussalam
| | - Rubens F Albuquerque
- Faculty of Dentistry of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, Brazil
| | - Ali Fakhry
- Faculty of Dentistry, McGill University, 2001 McGill College Avenue, Suite 500, Montreal, Quebec, H3A 1G1, Canada
| | - Sukhbir Kaur
- Department of Zoology, Panjab University, Chandigarh, India
| | - Jocelyne S Feine
- Faculty of Dentistry, McGill University, 2001 McGill College Avenue, Suite 500, Montreal, Quebec, H3A 1G1, Canada.
| |
Collapse
|
12
|
Grant SA, Smith SE, Schmidt H, Pfeiffer F, Kuroki K, Sherman S, White R, Grant DA. In vivo
bone tunnel evaluation of nanoparticle‐grafts using an ACL reconstruction rabbit model. J Biomed Mater Res A 2017; 105:1071-1082. [DOI: 10.1002/jbm.a.36000] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2016] [Revised: 12/27/2016] [Accepted: 01/06/2017] [Indexed: 01/13/2023]
Affiliation(s)
- Sheila A. Grant
- Department of BioengineeringUniversity of MissouriColumbia Missouri65211
| | - Sarah E. Smith
- Department of BioengineeringUniversity of MissouriColumbia Missouri65211
| | - Hilary Schmidt
- Department of BioengineeringUniversity of MissouriColumbia Missouri65211
| | - Ferris Pfeiffer
- Department of Orthopaedic SurgeryUniversity of MissouriColumbia Missouri65211
| | - Kei Kuroki
- Veterinary PathobiologyUniversity of MissouriColumbia Missouri65211
| | - Seth Sherman
- Department of Orthopaedic SurgeryUniversity of MissouriColumbia Missouri65211
| | - Richard White
- Department of Orthopaedic SurgeryAudrain Medical Center Mexico Missouri65265
| | - David A. Grant
- Department of BioengineeringUniversity of MissouriColumbia Missouri65211
| |
Collapse
|
13
|
Kantarci A, Hasturk H, Van Dyke TE. Animal models for periodontal regeneration and peri-implant responses. Periodontol 2000 2017; 68:66-82. [PMID: 25867980 DOI: 10.1111/prd.12052] [Citation(s) in RCA: 80] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/12/2013] [Indexed: 11/28/2022]
Abstract
Translation of experimental data to the clinical setting requires the safety and efficacy of such data to be confirmed in animal systems before application in humans. In dental research, the animal species used is dependent largely on the research question or on the disease model. Periodontal disease and, by analogy, peri-implant disease, are complex infections that result in a tissue-degrading inflammatory response. It is impossible to explore the complex pathogenesis of periodontitis or peri-implantitis using only reductionist in-vitro methods. Both the disease process and healing of the periodontal and peri-implant tissues can be studied in animals. Regeneration (after periodontal surgery), in response to various biologic materials with potential for tissue engineering, is a continuous process involving various types of tissue, including epithelia, connective tissues and alveolar bone. The same principles apply to peri-implant healing. Given the complexity of the biology, animal models are necessary and serve as the standard for successful translation of regenerative materials and dental implants to the clinical setting. Smaller species of animal are more convenient for disease-associated research, whereas larger animals are more appropriate for studies that target tissue healing as the anatomy of larger animals more closely resembles human dento-alveolar architecture. This review focuses on the animal models available for the study of regeneration in periodontal research and implantology; the advantages and disadvantages of each animal model; the interpretation of data acquired; and future perspectives of animal research, with a discussion of possible nonanimal alternatives. Power calculations in such studies are crucial in order to use a sample size that is large enough to generate statistically useful data, whilst, at the same time, small enough to prevent the unnecessary use of animals.
Collapse
|
14
|
Rydén L, Omar O, Johansson A, Jimbo R, Palmquist A, Thomsen P. Inflammatory cell response to ultra-thin amorphous and crystalline hydroxyapatite surfaces. JOURNAL OF MATERIALS SCIENCE. MATERIALS IN MEDICINE 2017; 28:9. [PMID: 27896599 PMCID: PMC5126180 DOI: 10.1007/s10856-016-5814-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2016] [Accepted: 11/08/2016] [Indexed: 05/04/2023]
Abstract
It has been suggested that surface modification with a thin hydroxyapatite (HA) coating enhances the osseointegration of titanium implants. However, there is insufficient information about the biological processes involved in the HA-induced response. This study aimed to investigate the inflammatory cell response to titanium implants with either amorphous or crystalline thin HA. Human mononuclear cells were cultured on titanium discs with a machined surface or with a thin, 0.1 μm, amorphous or crystalline HA coating. Cells were cultured for 24 and 96 h, with and without lipopolysaccharide (LPS) stimulation. The surfaces were characterized with respect to chemistry, phase composition, wettability and topography. Biological analyses included the percentage of implant-adherent cells and the secretion of pro-inflammatory cytokine (TNF-α) and growth factors (BMP-2 and TGF-β1). Crystalline HA revealed a smooth surface, whereas the amorphous HA displayed a porous structure, at nano-scale, and a hydrophobic surface. Higher TNF-α secretion and a higher ratio of adherent cells were demonstrated for the amorphous HA compared with the crystalline HA. TGF-β1 secretion was detected in all groups, but without any difference. No BMP-2 secretion was detected in any of the groups. The addition of LPS resulted in a significant increase in TNF-α in all groups, whereas TGF-β1 was not affected. Taken together, the results show that thin HA coatings with similar micro-roughness but a different phase composition, nano-scale roughness and wettability are associated with different monocyte responses. In the absence of strong inflammatory stimuli, crystalline hydroxyapatite elicits a lower inflammatory response compared with amorphous hydroxyapatite.
Collapse
Affiliation(s)
- Louise Rydén
- Department of Biomaterials, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, Box 412, Gothenburg, SE-405 30, Sweden
| | - Omar Omar
- Department of Biomaterials, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, Box 412, Gothenburg, SE-405 30, Sweden.
- BIOMATCELL, VINN Excellence Center of Biomaterials and Cell Therapy, Gothenburg, Sweden.
| | - Anna Johansson
- Department of Biomaterials, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, Box 412, Gothenburg, SE-405 30, Sweden
- BIOMATCELL, VINN Excellence Center of Biomaterials and Cell Therapy, Gothenburg, Sweden
| | - Ryo Jimbo
- Department of Oral and Maxillofacial Surgery and Oral Medicine, Faculty of Odontology, Malmö University, Malmö, Sweden
| | - Anders Palmquist
- Department of Biomaterials, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, Box 412, Gothenburg, SE-405 30, Sweden
- BIOMATCELL, VINN Excellence Center of Biomaterials and Cell Therapy, Gothenburg, Sweden
| | - Peter Thomsen
- Department of Biomaterials, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, Box 412, Gothenburg, SE-405 30, Sweden
- BIOMATCELL, VINN Excellence Center of Biomaterials and Cell Therapy, Gothenburg, Sweden
| |
Collapse
|
15
|
Staruch R, Griffin MF, Butler P. Nanoscale Surface Modifications of Orthopaedic Implants: State of the Art and Perspectives. Open Orthop J 2016; 10:920-938. [PMID: 28217214 PMCID: PMC5299555 DOI: 10.2174/1874325001610010920] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/10/2015] [Revised: 11/10/2015] [Accepted: 05/31/2016] [Indexed: 01/18/2023] Open
Abstract
Background: Orthopaedic implants such as the total hip or total knee replacement are examples of surgical interventions with postoperative success rates of over 90% at 10 years. Implant failure is associated with wear particles and pain that requires surgical revision. Improving the implant - bone surface interface is a key area for biomaterial research for future clinical applications. Current implants utilise mechanical, chemical or physical methods for surface modification. Methods: A review of all literature concerning the nanoscale surface modification of orthopaedic implant technology was conducted. Results: The techniques and fabrication methods of nanoscale surface modifications are discussed in detail, including benefits and potential pitfalls. Future directions for nanoscale surface technology are explored. Conclusion: Future understanding of the role of mechanical cues and protein adsorption will enable greater flexibility in surface control. The aim of this review is to investigate and summarise the current concepts and future directions for controlling the implant nanosurface to improve interactions.
Collapse
Affiliation(s)
- Rmt Staruch
- Department of Surgery & Interventional Science, University College London, London, England
| | - M F Griffin
- Department of Surgery & Interventional Science, University College London, London, England
| | - Pem Butler
- Department of Surgery & Interventional Science, University College London, London, England; University College London & The Royal Free Hospital, Pond Street, London, England
| |
Collapse
|
16
|
Yoon WJ, Kim SG, Oh JS, You JS, Jeong KI, Lim SC, Jeong MA. Comparative study on the osseointegration of implants in dog mandibles according to the implant surface treatment. J Korean Assoc Oral Maxillofac Surg 2016; 42:345-351. [PMID: 28053904 PMCID: PMC5206239 DOI: 10.5125/jkaoms.2016.42.6.345] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2015] [Revised: 02/26/2016] [Accepted: 02/26/2016] [Indexed: 02/05/2023] Open
Abstract
OBJECTIVES This study compared the impact of implant surface treatment on the stability and osseointegration of implants in dog mandibles. MATERIALS AND METHODS Six adult dogs received a total of 48 implants that were prepared using four different surface treatments; resorbable blast media (RBM), hydroxyapatite (HA), hydrothermal-treated HA, and sand blasting and acid etching (SLA). Implants were installed, and dogs were separated into 2- and 4-week groups. Implant stability was evaluated via Periotest M, Osstell Mentor, and removal torque analyzers. A histomorphometric analysis was also performed. RESULTS The stability evaluation showed that all groups generally had satisfactory values. The histomorphometric evaluation via a light microscope revealed that the HA surface implant group had the highest ratio of new bone formation on the entire fixture. The hydrothermal-treated HA surface implant group showed a high ratio of bone-to-implant contact in the upper half of the implant area. CONCLUSION The hydrothermal-treated HA implant improved the bone-to-implant contact ratio on the upper fixture, which increased the implant stability.
Collapse
Affiliation(s)
- Wook-Jae Yoon
- Department of Oral and Maxillofacial Surgery, School of Dentistry, Chosun University, Gwangju, Korea
| | - Su-Gwan Kim
- Department of Oral and Maxillofacial Surgery, School of Dentistry, Chosun University, Gwangju, Korea
| | - Ji-Su Oh
- Department of Oral and Maxillofacial Surgery, School of Dentistry, Chosun University, Gwangju, Korea
| | - Jae-Seek You
- Department of Oral and Maxillofacial Surgery, School of Dentistry, Chosun University, Gwangju, Korea
| | - Kyung-In Jeong
- Department of Oral and Maxillofacial Surgery, Section of Dentistry, Konyang University Hospital, Daejeon, Korea
| | - Sung-Chul Lim
- Department of Pathology, School of Medicine, Chosun University, Gwangju, Korea
| | - Mi-Ae Jeong
- Department of Dental Hygiene, Kangwon National University, Samcheok, Korea
| |
Collapse
|
17
|
Li X, Liu X, Wu S, Yeung KWK, Zheng Y, Chu PK. Design of magnesium alloys with controllable degradation for biomedical implants: From bulk to surface. Acta Biomater 2016; 45:2-30. [PMID: 27612959 DOI: 10.1016/j.actbio.2016.09.005] [Citation(s) in RCA: 227] [Impact Index Per Article: 28.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2016] [Revised: 08/31/2016] [Accepted: 09/02/2016] [Indexed: 01/24/2023]
Abstract
The combination of high strength, light weight, and natural biodegradability renders magnesium (Mg)-based alloys promising in orthopedic implants and cardiovascular stents. Being metallic materials, Mg and Mg alloys made for scaffolds provide the necessary mechanical support for tissue healing and cell growth in the early stage, while natural degradation and reabsorption by surrounding tissues in the later stage make an unnecessarily follow-up removal surgery. However, uncontrolled degradation may collapse the scaffolds resulting in premature implant failure, and there has been much research in controlling the degradation rates of Mg alloys. This paper reviews recent progress in the design of novel Mg alloys, surface modification and corrosion mechanisms under different conditions, and describes the effects of the structure, composition, and surface conditions on the degradation behavior in vitro and in vivo. STATEMENT OF SIGNIFICANCE Owing to their unique mechanical properties, biodegradability, biocompatibility, Mg based biomaterials are becoming the most promising substitutes for tissue regeneration for impaired bone, vascular and other tissues because these scaffolds can provide not only ideal space for the growth and differentiation of seeded cells but also enough strength before the formation of normal tissues. The most important is that these scaffolds can be fully degraded after tissue regeneration, which can satisfy the increasing demand for better biomedical devices and functional tissue engineering biomaterials in the world. However, the rapid degradation rate of these scaffolds restricts the wide application in clinic. This paper reviews recent progress on how to control the degrdation rate based on the relevant corrosion mechanisms through the design of porous structure, phase structure, grains, and amorphous structure as well as surface modification, which will be beneficial to the better understanding and functional design of Mg-based scaffolds for wide clinical applications in tissue reconstruction in near futures.
Collapse
Affiliation(s)
- Xia Li
- Hubei Collaborative Innovation Center for Advanced Organic Chemical Materials, Ministry-of-Education Key Laboratory for the Green Preparation and Application of Functional Materials, Hubei Key Laboratory of Polymer Materials, Faculty of Materials Science & Engineering, Hubei University, Wuhan 430062, China
| | - Xiangmei Liu
- Hubei Collaborative Innovation Center for Advanced Organic Chemical Materials, Ministry-of-Education Key Laboratory for the Green Preparation and Application of Functional Materials, Hubei Key Laboratory of Polymer Materials, Faculty of Materials Science & Engineering, Hubei University, Wuhan 430062, China.
| | - Shuilin Wu
- Hubei Collaborative Innovation Center for Advanced Organic Chemical Materials, Ministry-of-Education Key Laboratory for the Green Preparation and Application of Functional Materials, Hubei Key Laboratory of Polymer Materials, Faculty of Materials Science & Engineering, Hubei University, Wuhan 430062, China.
| | - K W K Yeung
- Division of Spine Surgery, Department of Orthopaedics & Traumatology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China
| | - Yufeng Zheng
- State Key Laboratory for Turbulence and Complex System and Department of Materials Science and Engineering, College of Engineering, Peking University, Beijing 100871, China
| | - Paul K Chu
- Department of Physics & Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong, China.
| |
Collapse
|
18
|
Klimek K, Belcarz A, Pazik R, Sobierajska P, Han T, Wiglusz RJ, Ginalska G. “False” cytotoxicity of ions-adsorbing hydroxyapatite — Corrected method of cytotoxicity evaluation for ceramics of high specific surface area. MATERIALS SCIENCE & ENGINEERING. C, MATERIALS FOR BIOLOGICAL APPLICATIONS 2016; 65:70-9. [DOI: 10.1016/j.msec.2016.03.105] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2016] [Revised: 03/22/2016] [Accepted: 03/29/2016] [Indexed: 11/28/2022]
|
19
|
In vivo biofunctionalization of titanium patient-specific implants with nano hydroxyapatite and other nano calcium phosphate coatings: A systematic review. J Craniomaxillofac Surg 2016; 44:400-12. [DOI: 10.1016/j.jcms.2015.12.004] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2015] [Revised: 11/05/2015] [Accepted: 12/11/2015] [Indexed: 12/22/2022] Open
|
20
|
Besinis A, De Peralta T, Tredwin CJ, Handy RD. Review of nanomaterials in dentistry: interactions with the oral microenvironment, clinical applications, hazards, and benefits. ACS NANO 2015; 9:2255-2289. [PMID: 25625290 DOI: 10.1021/nn505015e] [Citation(s) in RCA: 132] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Interest in the use of engineered nanomaterials (ENMs) as either nanomedicines or dental materials/devices in clinical dentistry is growing. This review aims to detail the ultrafine structure, chemical composition, and reactivity of dental tissues in the context of interactions with ENMs, including the saliva, pellicle layer, and oral biofilm; then describes the applications of ENMs in dentistry in context with beneficial clinical outcomes versus potential risks. The flow rate and quality of saliva are likely to influence the behavior of ENMs in the oral cavity, but how the protein corona formed on the ENMs will alter bioavailability, or interact with the structure and proteins of the pellicle layer, as well as microbes in the biofilm, remains unclear. The tooth enamel is a dense crystalline structure that is likely to act as a barrier to ENM penetration, but underlying dentinal tubules are not. Consequently, ENMs may be used to strengthen dentine or regenerate pulp tissue. ENMs have dental applications as antibacterials for infection control, as nanofillers to improve the mechanical and bioactive properties of restoration materials, and as novel coatings on dental implants. Dentifrices and some related personal care products are already available for oral health applications. Overall, the clinical benefits generally outweigh the hazards of using ENMs in the oral cavity, and the latter should not prevent the responsible innovation of nanotechnology in dentistry. However, the clinical safety regulations for dental materials have not been specifically updated for ENMs, and some guidance on occupational health for practitioners is also needed. Knowledge gaps for future research include the formation of protein corona in the oral cavity, ENM diffusion through clinically relevant biofilms, and mechanistic investigations on how ENMs strengthen the tooth structure.
Collapse
Affiliation(s)
| | - Tracy De Peralta
- ‡Plymouth University Peninsula Dental School, University of Plymouth, John Bull Building, Tamar Science Park, Plymouth PL6 8BU, U.K
| | - Christopher J Tredwin
- ‡Plymouth University Peninsula Dental School, University of Plymouth, John Bull Building, Tamar Science Park, Plymouth PL6 8BU, U.K
| | | |
Collapse
|
21
|
Cho Y, Hong J, Ryoo H, Kim D, Park J, Han J. Osteogenic responses to zirconia with hydroxyapatite coating by aerosol deposition. J Dent Res 2015; 94:491-9. [PMID: 25586588 DOI: 10.1177/0022034514566432] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Previously, we found that osteogenic responses to zirconia co-doped with niobium oxide (Nb2O5) or tantalum oxide (Ta2O5) are comparable with responses to titanium, which is widely used as a dental implant material. The present study aimed to evaluate the in vitro osteogenic potential of hydroxyapatite (HA)-coated zirconia by an aerosol deposition method for improved osseointegration. Surface analysis by scanning electron microscopy and x-ray diffraction proved that a thin as-deposited HA film on zirconia showed a shallow, regular, crater-like surface. Deposition of dense and uniform HA films was measured by SEM, and the contact angle test demonstrated improved wettability of the HA-coated surface. Confocal laser scanning microscopy indicated that MC3T3-E1 pre-osteoblast attachment did not differ notably between the titanium and zirconia surfaces; however, cells on the HA-coated zirconia exhibited a lower proliferation than those on the uncoated zirconia late in the culture. Nevertheless, ALP, alizarin red S staining, and bone marker gene expression analysis indicated good osteogenic responses on HA-coated zirconia. Our results suggest that HA-coating by aerosol deposition improves the quality of surface modification and is favorable to osteogenesis.
Collapse
Affiliation(s)
- Y Cho
- Department of Prosthodontics, School of Dentistry and Dental Research Institute, BK21 Program, Seoul National University, Seoul, Korea Department of Periodontology, School of Dentistry and Dental Research Institute, BK21 Program, Seoul National University, Seoul, Korea Department of Molecular Genetics, School of Dentistry and Dental Research Institute, BK21 Program, Seoul National University, Seoul, Korea
| | - J Hong
- Department of Prosthodontics, School of Dentistry and Dental Research Institute, BK21 Program, Seoul National University, Seoul, Korea
| | - H Ryoo
- Department of Molecular Genetics, School of Dentistry and Dental Research Institute, BK21 Program, Seoul National University, Seoul, Korea
| | - D Kim
- Department of Advanced Materials Engineering, Sejong University, Seoul, Korea
| | - J Park
- R&D Center, Nano Business, IONES Co., Ltd., Gyeonggi-do, Korea
| | - J Han
- Department of Prosthodontics, School of Dentistry and Dental Research Institute, BK21 Program, Seoul National University, Seoul, Korea
| |
Collapse
|
22
|
Jung HD, Jang TS, Wang L, Kim HE, Koh YH, Song J. Novel strategy for mechanically tunable and bioactive metal implants. Biomaterials 2015; 37:49-61. [DOI: 10.1016/j.biomaterials.2014.10.027] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2014] [Accepted: 10/02/2014] [Indexed: 01/15/2023]
|
23
|
Wu S, Tu B, Lin J, Wang Z, Wang X, Shen M, Hu R. Evaluation of the biocompatibility of a hydroxyapatite-CaTiO3 coating in vivo. Biocybern Biomed Eng 2015. [DOI: 10.1016/j.bbe.2015.05.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
|
24
|
Sörensen JH, Dürselen L, Welch K, Sörensen TC, Procter P, Engqvist H, Strømme M, Ignatius A, Steckel H. Biomimetic Hydroxyapatite Coated Titanium Screws Demonstrate Rapid Implant Stabilization and Safe Removal <i>In-Vivo</i>. ACTA ACUST UNITED AC 2015. [DOI: 10.4236/jbnb.2015.61003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
|
25
|
Zhao SF, Dong WJ, Jiang QH, He FM, Wang XX, Yang GL. Effects of zinc-substituted nano-hydroxyapatite coatings on bone integration with implant surfaces. J Zhejiang Univ Sci B 2014; 14:518-25. [PMID: 23733429 DOI: 10.1631/jzus.b1200327] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
OBJECTIVE The purpose of this study was to investigate the effects of a zinc-substituted nano-hydroxyapatite (Zn-HA) coating, applied by an electrochemical process, on implant osseointegraton in a rabbit model. METHODS A Zn-HA coating or an HA coating was deposited using an electrochemical process. Surface morphology was examined using field-emission scanning electron microscopy. The crystal structure and chemical composition of the coatings were examined using an X-ray diffractometer (XRD) and Fourier transform infrared spectroscopy (FTIR). A total of 78 implants were inserted into femurs and tibias of rabbits. After two, four, and eight weeks, femurs and tibias were retrieved and prepared for histomorphometric evaluation and removal torque (RTQ) tests. RESULTS Rod-like HA crystals appeared on both implant surfaces. The dimensions of the Zn-HA crystals seemed to be smaller than those of HA. XRD patterns showed that the peaks of both coatings matched well with standard HA patterns. FTIR spectra showed that both coatings consisted of HA crystals. The Zn-HA coating significantly improved the bone area within all threads after four and eight weeks (P<0.05), the bone to implant contact (BIC) at four weeks (P<0.05), and RTQ values after four and eight weeks (P<0.05). CONCLUSIONS The study showed that an electrochemically deposited Zn-HA coating has potential for improving bone integration with an implant surface.
Collapse
Affiliation(s)
- Shi-fang Zhao
- Department of Oral Implantology, Affiliated Stomatology Hospital, School of Medicine, Zhejiang University, Hangzhou 310006, China
| | | | | | | | | | | |
Collapse
|
26
|
Osteoblast responses to thin nanohydroxyapatite coated on roughened titanium surfaces deposited by an electrochemical process. Oral Surg Oral Med Oral Pathol Oral Radiol 2013; 116:e311-6. [DOI: 10.1016/j.oooo.2012.02.021] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2011] [Revised: 02/09/2012] [Accepted: 02/21/2012] [Indexed: 11/22/2022]
|
27
|
Bryington MS, Hayashi M, Kozai Y, Vandeweghe S, Andersson M, Wennerberg A, Jimbo R. The influence of nano hydroxyapatite coating on osseointegration after extended healing periods. Dent Mater 2013; 29:514-20. [DOI: 10.1016/j.dental.2013.02.004] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2012] [Revised: 12/14/2012] [Accepted: 02/12/2013] [Indexed: 11/24/2022]
|
28
|
Cheng Z, Guo C, Dong W, He FM, Zhao SF, Yang GL. Effect of thin nano-hydroxyapatite coating on implant osseointegration in ovariectomized rats. Oral Surg Oral Med Oral Pathol Oral Radiol 2013; 113:e48-53. [PMID: 22669157 DOI: 10.1016/j.tripleo.2011.07.008] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2010] [Revised: 06/30/2011] [Accepted: 07/04/2011] [Indexed: 11/26/2022]
Abstract
PURPOSE The purpose of this study was to investigate the effect of the thin nano-hydroxyapatite (nano-HA) coating on implant osseointegration in an ovariectomized rat model. MATERIALS AND METHODS Implants were divided into a control group and a test group (nano-HA-coated group). Surface morphology was examined using field-emission scanning electron microscopy (FSEM). Surface roughness of both groups was performed. Sixteen ovariectomized rats randomly received 2 implants in both tibiae. After 12 weeks of implantation, tibias were retrieved and prepared for histomorphometric evaluation and removal torque tests (RTQ). RESULTS Rodlike crystals uniformly covered the porous surfaces and the surface morphology of the implant was still clear. No significant differences were found in surface roughness between the 2 groups (P > .05). More bone tissue was formed around test implants compared with control implants. Test implants showed a significantly greater BIC, bone area within all threads, and RTQ values compared with control implants (P < .05). CONCLUSIONS These results indicate the thin nano-HA coating by an electrochemical process has potential benefits to enhance implant osseointegration in ovariectomized rats.
Collapse
Affiliation(s)
- Zhipeng Cheng
- Department of Implantology, Stomatology Hospital, School of Medical, Zhejiang University, Yan'an Road, Hangzhou, China
| | | | | | | | | | | |
Collapse
|
29
|
Zhou C, Hong Y, Zhang X. Applications of nanostructured calcium phosphate in tissue engineering. Biomater Sci 2013; 1:1012-1028. [DOI: 10.1039/c3bm60058k] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
|
30
|
Fu DL, Jiang QH, He FM, Yang GL, Liu L. Fluorescence microscopic analysis of bone osseointegration of strontium-substituted hydroxyapatite implants. J Zhejiang Univ Sci B 2012; 13:364-71. [PMID: 22556174 DOI: 10.1631/jzus.b1100381] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The purpose of this study was to analyze the effect of strontium-substituted hydroxyapatite (Sr-HA) on bone osseointegration of the implants using fluorescence microscopy. We allocated 20 implants to two groups: Sr-HA group and HA group. Electrochemically deposited HA and Sr-HA coatings were applied onto the implants separately. All the implants were inserted into femur bone of rabbits. Oxytetracycline hydrochloride, alizarin-complexon, and calcein green were respectively administered 7, 28, and 46 d after the implantation. After eight weeks, femurs were retrieved and prepared for the fluorescence microscopy observation. We analyzed the bone mineral apposition rates (MARs), bone area ratios (BARs), and bone to implant contact (BIC) of the two groups. Fluorescence microscopic observation showed that all groups exhibited extensive early peri-implant bone formation. The MAR of the Sr-HA group was greater than that for pure HA from 7 to 28 d after implantation, but no significant difference was found at later stage. And the BIC showed difference at 7 and 28 d compared with pure HA. We concluded that Sr-HA coating can improve the bone osseointegration of the implant in the early stage compared with the HA coating.
Collapse
Affiliation(s)
- Dan-li Fu
- Department of General Dentistry, Stomatology Hospital, School of Medicine, Zhejiang University, Hangzhou, China
| | | | | | | | | |
Collapse
|
31
|
Agholme F, Andersson T, Tengvall P, Aspenberg P. Local bisphosphonate release versus hydroxyapatite coating for stainless steel screw fixation in rat tibiae. JOURNAL OF MATERIALS SCIENCE. MATERIALS IN MEDICINE 2012; 23:743-752. [PMID: 22203517 DOI: 10.1007/s10856-011-4539-5] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2011] [Accepted: 12/14/2011] [Indexed: 05/31/2023]
Abstract
Implant fixation in bone can be improved by a coating that delivers bisphosphonates locally, or by a hydroxyapatite (HA) coating. In this study, we compared these different types of coatings. For mechanical testing, 30 rats were assigned into three groups, and similar screws were implanted bilaterally in the proximal tibiae. The rats received screws that were either uncoated, coated with nano-crystalline hydroxyapatite or coated with a bisphosphonate releasing protein matrix. After 4 weeks, one screw was subjected to pull-out testing, and the contra-lateral one to torsion testing. For morphology, 30 rats were assigned to similar treatment groups, but received only one screw each. Bisphosphonates enhanced the pull-out force by 41% (P = 0.02) compared to controls, HA increased the pull-out force although not significantly. Conversely, HA increased the maximal torque by 64% (P = 0.02). Morphometry showed higher bone volume around bisphosphonate screws in comparison to HA-coated screws (P < 0.001) and controls (P < 0.001). The results suggest that bisphosphonates improve fixation by increasing the amount of surrounding bone, whereas HA mainly improves bone to implant attachment.
Collapse
Affiliation(s)
- F Agholme
- Orthopedics, Department of Clinical and Experimental Medicine, Faculty of Medicine, Linköping University, Linköping, Sweden
| | | | | | | |
Collapse
|
32
|
Osteoblast response to porous titanium surfaces coated with zinc-substituted hydroxyapatite. Oral Surg Oral Med Oral Pathol Oral Radiol 2012; 113:313-8. [DOI: 10.1016/j.tripleo.2011.02.049] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2011] [Accepted: 02/22/2011] [Indexed: 11/20/2022]
|
33
|
Yang F, Zhang R, He F, Wang XX, Zhao S, Yang G. Osteoblast response to puerarin-loaded porous titanium surfaces: an in vitro study. J Biomed Mater Res A 2012; 100:1419-26. [PMID: 22374837 DOI: 10.1002/jbm.a.34080] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2011] [Accepted: 01/06/2012] [Indexed: 11/07/2022]
Abstract
Recent studies demonstrate puerarin stimulates bone formation, suggesting its potential application in dental implantology field. The aim of this study was to investigate effects of puerarin-loaded titanium surfaces on the promotion of osteogenesis in preosteoblasts (MC3T3-E1). Puerarin was prepared onto titanium surfaces with varying concentration (10(-9) M, 10(-8) M, 10(-7) M, and 10(-6) M) by biomimetic calcium phosphate deposition process. Surface characteristics were performed by field-emission scanning electron microscope (FSEM), X-ray diffractometer (XRD), and Fourier transform infrared spectroscopy (FTIR). Puerarin concentration in the coatings was performed by High-performance liquid chromatograph (HPLC) analyses. FSEM observation showed puerarin concentration influenced formation of sharp flakes in the coating. The size of flakes decreased with increase of puerarin concentrations. XRD and FTIR examinations demonstrated the puerarin concentration did not affect the chemical compositions of coatings, which composed of octacalcium phosphate (OCP). Puerarin concentration on the surfaces of 10(-8) M group was 10.22 ± 0.32 ng/cm(2) . Puerarin had an increased effect on MC3T3-E1 ALP activities. Significant differences were found in 10(-8) and 10(-7) M groups on day 4, 10(-8) , 10(-7) , and 10(-6) M groups on day 7, and 10(-8) on day 14. In Type I collagen synthesis assay, 10(-9) and 10(-8) M on day 7, 10(-8) on day 14 showed significant differences compared with control group. Furthermore, this stimulatory effect of puerarin was also observed in osteocalcin release assay (p < 0.05, at 10(-8) M and 10(-7) M, maximal at 10(-8) M). These results indicate puerarin-loaded titanium surfaces promote accelerated osteogenic differentiation of preosteoblasts, which has the potential to improve the nature of osseointegration.
Collapse
Affiliation(s)
- Fan Yang
- Department of Implantology, Stomatology Hospital, School of Medical, Zhejiang university, Yan'an Road, Hangzhou, China
| | | | | | | | | | | |
Collapse
|
34
|
Zhao SF, Jiang QH, Peel S, Wang XX, He FM. Effects of magnesium-substituted nanohydroxyapatite coating on implant osseointegration. Clin Oral Implants Res 2011; 24 Suppl A100:34-41. [PMID: 22145854 DOI: 10.1111/j.1600-0501.2011.02362.x] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/01/2011] [Indexed: 11/30/2022]
Affiliation(s)
- Shi-fang Zhao
- Department of Oral and Maxillofacial Surgery; The Affiliated Stomatology Hospital; School of Medicine; Zhejiang University; Hangzhou; China
| | - Qiao-hong Jiang
- Department of Oral Implantology; The Affiliated Stomatology Hospital; School of Medicine; Zhejiang University; Hangzhou; China
| | - Sean Peel
- Discipline of Oral & Maxillofacial Surgery; Faculty of Dentistry; University of Toronto; Toronto; ON; Canada
| | - Xiao-xiang Wang
- Department of Materials Science and Engineering; Zhejiang University; Hangzhou; China
| | | |
Collapse
|
35
|
Svanborg L, Hoffman M, Andersson M, Currie F, Kjellin P, Wennerberg A. The effect of hydroxyapatite nanocrystals on early bone formation surrounding dental implants. Int J Oral Maxillofac Surg 2011; 40:308-15. [DOI: 10.1016/j.ijom.2010.10.010] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2010] [Revised: 10/05/2010] [Accepted: 10/07/2010] [Indexed: 10/18/2022]
|
36
|
Variola F, Brunski J, Orsini G, de Oliveira PT, Wazen R, Nanci A. Nanoscale surface modifications of medically relevant metals: state-of-the art and perspectives. NANOSCALE 2011; 3:335-53. [PMID: 20976359 PMCID: PMC3105323 DOI: 10.1039/c0nr00485e] [Citation(s) in RCA: 116] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Evidence that nanoscale surface properties stimulate and guide various molecular and biological processes at the implant/tissue interface is fostering a new trend in designing implantable metals. Cutting-edge expertise and techniques drawn from widely separated fields, such as nanotechnology, materials engineering and biology, have been advantageously exploited to nanoengineer surfaces in ways that control and direct these processes in predictable manners. In this review, we present and discuss the state-of-the-art of nanotechnology-based approaches currently adopted to modify the surface of metals used for orthopedic and dental applications, and also briefly consider their use in the cardiovascular field. The effects of nanoengineered surfaces on various in vitro molecular and cellular events are firstly discussed. This review also provides an overview of in vivo and clinical studies with nanostructured metallic implants, and addresses the potential influence of nanotopography on biomechanical events at interfaces. Ultimately, the objective of this work is to give the readership a comprehensive picture of the current advances, future developments and challenges in the application of the infinitesimally small to biomedical surface science. We believe that an integrated understanding of the in vitro and particularly of the in vivo behavior is mandatory for the proper exploitation of nanostructured implantable metals and, indeed, of all biomaterials.
Collapse
Affiliation(s)
- Fabio Variola
- Faculty of Engineering, Department of Mechanical Engineering, University of Ottawa, Ottawa, ON, K1N 6N5 (Canada)
- Laboratory for the Study of Calcified Tissues and Biomaterials, Faculté de Médecine Dentaire, Université de Montréal, Montréal, QC, H3C 3J7 (Canada)
| | - John Brunski
- Division of Plastic & Reconstructive Surgery, Department of Surgery PSRL, School of Medicine, Stanford University, 257 Campus Drive Stanford, CA 94305 (USA)
| | - Giovanna Orsini
- Department of Clinical Sciences and Stomatology, University of Marche, Via Tronto 10, 66026 Ancona (Italy)
| | - Paulo Tambasco de Oliveira
- Department of Morphology, Stomatology and Physiology, University of São Paulo, Ribeirão Preto, SP, 14040-904 (Brazil)
| | - Rima Wazen
- Laboratory for the Study of Calcified Tissues and Biomaterials, Faculté de Médecine Dentaire, Université de Montréal, Montréal, QC, H3C 3J7 (Canada)
| | - Antonio Nanci
- Laboratory for the Study of Calcified Tissues and Biomaterials, Faculté de Médecine Dentaire, Université de Montréal, Montréal, QC, H3C 3J7 (Canada)
| |
Collapse
|
37
|
Creating Electrospun Nanofiber-Based Biomimetic Scaffolds for Bone Regeneration. BIOMEDICAL APPLICATIONS OF POLYMERIC NANOFIBERS 2011. [DOI: 10.1007/12_2011_131] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
|