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Durability of Cell Adhesion Peptides Coatings for Dental Implants. Dent Mater 2022. [DOI: 10.1016/j.dental.2021.12.120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Verification of Collagenase Production by Streptococcus Mutans. Dent Mater 2022. [DOI: 10.1016/j.dental.2021.12.113] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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PO-1978 Chronic and cosmetic toxicity in patients undergoing radiotherapy and breast reconstruction. Radiother Oncol 2021. [DOI: 10.1016/s0167-8140(21)08429-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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4
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Microstructural Evaluation of Alloy 800H After SCWL Exposure. JOURNAL OF NUCLEAR ENGINEERING AND RADIATION SCIENCE 2021. [DOI: 10.1115/1.4049853] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Abstract
Alloy 800H is a candidate material for supercritical water-cooled reactors (SCWR), specifically for in-core components in Canadian-type SCWR, that will operate at a pressure of 25 MPa and a core temperature from 350 °C to 625 °C. To evaluate this, several exposures to supercritical water took place at 395 °C and 25 MPa in a supercritical water loop (SCWL). The duration of each exposure was 500, 150, and 1000 h. Scanning electron microscopy (SEM) with electron backscatter diffraction (EBSD), in combination with Raman spectroscopy (RS) and X-ray diffraction (XRD), was used to evaluate the microstructure of alloy 800H after the exposures to supercritical water. All these methods confirmed the presence of magnetite and trevorite/chromite crystals, with a thickness of less than 1 μm, on the surface after each exposure. No significant change occurred after the second and third exposures. The matrix crystallography did not change during the exposures and demonstrated grain twinning with a grain size of 100–400 μm.
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On the rapid in situ oxidation of two-dimensional V 2CT z MXene in culture cell media and their cytotoxicity. MATERIALS SCIENCE & ENGINEERING. C, MATERIALS FOR BIOLOGICAL APPLICATIONS 2020; 119:111431. [PMID: 33321581 DOI: 10.1016/j.msec.2020.111431] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2020] [Revised: 07/24/2020] [Accepted: 08/20/2020] [Indexed: 01/11/2023]
Abstract
The plethora of emerging two-dimensional (2D) materials exhibit wide potential application in novel technologies and advanced devices. However, their stability in environmental conditions could be an issue, affecting their application possibilities and posing health risks. Moreover, their decomposed leftovers can also induce a negative influence on human health. In particular, transition metal carbides commonly referred to as MXenes are susceptible to environmental oxidation being decomposed toward transition metal oxides and carbide-derived carbon. In this study we focused on the oxidation-state-related in vitro cytotoxicity of delaminated V2CTz onto immortalized keratinocytes (HaCaT) and malignant melanoma (A375) human cell lines. Due to the fact, that the V2CTx MXenes are least stable from all known obtained MXenes up to date, the vanadium ones were a practical choice to visualize the oxidation-cytotoxic correlation keeping the standards of 24-48 h of cell culturing. We found that the oxidation of V2CTz highly increases their cytotoxicity toward human cells, which is also time and dose dependent. The identified mode of action relates to the cell cycle as well as cellular membrane disintegration through direct physicochemical interactions.
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Abstract
The evolution of bonded restorations has undergone great progress over several decades. Nonetheless, life spans of bonded restorations are limited mainly because of the eventual incidence of recurrent caries. Over time, water and waterborne agents (acids, enzymes) degrade the components of the dentin/restoration interface, allowing bacterial colonization and dentin reinfection at the margins of the restoration. We developed a 2-tier protective technology consisting of priming/coating dentin with amphipathic and antimicrobial peptides (AAMPs) to obtain hydrophobic/water-repellent and antibiofilm dentin-resisting recurrent caries around bonded restorations. We tested a series of AAMPs to assess their structure-function relationships as well as the effects of different dentin-conditioning methods on the structural features of AAMP-coated dentin. We found relation between the secondary structure of AAMPs (high portion of β-sheet), the antimicrobial potency of AAMPs, and the AAMPs' ability to form hydrophobic coatings on dentin. We also determined that AAMPs had preferential adsorption on the mineral phase of dentin, which suggested that peptides arrange their cationic and hydrophilic motifs in direct contact with the negatively charged minerals in the hydrophilic dentin. These results led us to explore different dentin-conditioning methods that would increase the mineral/collagen ratio and their effect on AAMP immobilization. We innovatively imaged the spatial distribution of the AAMPs in relation to the dentinal tubules and collagen network using a minimally invasive multimodal imaging technique: multiphoton-second harmonic generation. Using multiphoton-second harmonic generation imaging, we determined that partial deproteinization of dentin increased the amount of immobilized AAMPs as compared with the total etched dentin at the dentin surface and extended deeply around dentinal tubules. Last, we analyzed the release rate of AAMPs from dentin coatings in artificial saliva to predict their stability in the clinical setting. In conclusion, priming dentin with AAMPs is a versatile new approach with potential to fortify the otherwise vulnerable adhesive-based interfaces.
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In vivo osseointegration of dental implants with an antimicrobial peptide coating. JOURNAL OF MATERIALS SCIENCE. MATERIALS IN MEDICINE 2017; 28:76. [PMID: 28386851 DOI: 10.1007/s10856-017-5885-8] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/28/2016] [Accepted: 03/15/2017] [Indexed: 06/07/2023]
Abstract
This study aimed to evaluate the in vivo osseointegration of implants with hydrophobic antimicrobial GL13K-peptide coating in rabbit femoral condyles by micro-CT and histological analysis. Six male Japanese Rabbits (4 months old and weighing 2.5 kg each) were included in this study. Twelve implants (3.75 mm wide, 7 mm long) were randomly distributed in two groups, with six implants in the experimental group coated with GL13K peptide and six implants in the control group without surface coating. Each implant in the test and the control group was randomly implanted in the left or right side of femoral condyles. On one side randomly-selected of the femur, each rabbit received a drill that was left without implant as control for the natural healing of bone. After 3 weeks of healing radiographic evaluation of the implant sites was taken. After 6 weeks of healing, rabbits were sacrificed for evaluation of the short-term osseointegration of the dental implants using digital radiography, micro-CT and histology analysis. To perform evaluation of osseointegration, implant location and group was double blinded for surgeon and histology/radiology researcher. Two rabbits died of wound infection in sites with non-coated implants 2 weeks after surgery. Thus, at least four rabbits per group survived after 6 weeks of healing. The wounds healed without suppuration and inflammation. No implant was loose after 6 weeks of healing. Radiography observations showed good osseointegration after 3 and 6 weeks postoperatively, which proved that the tissues followed a natural healing process. Micro-CT reconstruction and analysis showed that there was no statistically significant difference (P > 0.05) in volume of bone around the implant between implants coated with GL13K peptide and implants without coating. Histomorphometric analysis also showed that the mineralized bone area was no statistically different (P > 0.05) between implants coated with GL13K peptide and implants without coating. This study demonstrates that titanium dental implants with an antimicrobial GL13K coating enables in vivo implant osseointegration at similar bone growth rates than gold-standard non-coated dental implants up to 6 weeks of implantation in rabbit femurs.
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Human BRS-3 receptor: functions/role in cell signaling pathways and glucose metabolism in obese or diabetic myocytes. Peptides 2014; 51:91-9. [PMID: 24220502 DOI: 10.1016/j.peptides.2013.11.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/16/2013] [Revised: 11/04/2013] [Accepted: 11/04/2013] [Indexed: 10/26/2022]
Abstract
Several studies showed that the orphan Bombesin Receptor Subtype-3 (BRS-3) - member of the bombesin receptor family - has an important role in glucose homeostasis (v.g.: BRS-3-KO mice developed mild obesity, and decreased levels of BRS-3 mRNA/protein have been described in muscle from obese (OB) and type 2 diabetic (T2D) patients). In this work, to gain insight into BRS-3 receptor cell signaling pathways, and its implication on glucose metabolism, primary cultured myocytes from normal subjects, OB or T2D patients were tested using high affinity ligand - [d-Tyr(6),β-Ala(11),Phe(13),Nle(14)]bombesin6-14. In muscle cells from all metabolic conditions, the compound significantly increased not only MAPKs, p90RSK1, PKB and p70s6K phosphorylation levels, but also PI3K activity; moreover, it produced a dose-response stimulation of glycogen synthase a activity and glycogen synthesis. Myocytes from OB and T2D patients were more sensitive to the ligand than normal, and T2D cells even more than obese myocytes. These results widen the knowledge of human BRS-3 cell signaling pathways induced by a BRS-3 agonist, described its insulin-mimetic effects on glucose metabolism, showed the role of BRS-3 receptor in glucose homeostasis, and also propose the employing of BRS-3/ligand system, as participant in the obese and diabetic therapies.
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MESH Headings
- Adult
- Aged
- Bombesin/pharmacology
- Cells, Cultured
- Diabetes Mellitus, Type 2/metabolism
- Diabetes Mellitus, Type 2/pathology
- Female
- Glucose/metabolism
- Glycogen/biosynthesis
- Glycogen Synthase/metabolism
- Homeostasis
- Humans
- Male
- Middle Aged
- Mitogen-Activated Protein Kinases/metabolism
- Muscle Fibers, Skeletal/drug effects
- Muscle Fibers, Skeletal/metabolism
- Obesity/metabolism
- Obesity/pathology
- Peptide Fragments/pharmacology
- Phosphatidylinositol 3-Kinases/metabolism
- Phosphorylation
- Protein Processing, Post-Translational
- Proto-Oncogene Proteins c-akt/metabolism
- Receptors, Bombesin/agonists
- Receptors, Bombesin/physiology
- Ribosomal Protein S6 Kinases, 70-kDa/metabolism
- Ribosomal Protein S6 Kinases, 90-kDa/metabolism
- Signal Transduction
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Antimicrobial properties and dentin bonding strength of magnesium phosphate cements. Acta Biomater 2013; 9:8384-93. [PMID: 23747324 DOI: 10.1016/j.actbio.2013.05.032] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2013] [Revised: 05/26/2013] [Accepted: 05/28/2013] [Indexed: 11/30/2022]
Abstract
The main objective of this work was to assess the antimicrobial properties and the dentin-bonding strength of novel magnesium phosphate cements (MPC). Three formulations of MPC, consisting of magnesium oxide and a phosphate salt, NH4H2PO4, NaH2PO4 or a mixture of both, were evaluated. As a result of the setting reaction, MPC transformed into either struvite (MgNH4PO4·6H2O) when NH4H2PO4 was used or an amorphous magnesium sodium phosphate when NaH2PO4 was used. The MPC had appropriate setting times for hard tissue applications, high early compressive strengths and higher strength of bonding to dentin than commercial mineral trioxide aggregate cement. Bacteriological studies were performed with fresh and aged cements against three bacterial strains, Escherichia coli, Pseudomonas aeruginosa (planktonic and in biofilm) and Aggregatibacter actinomycetemcomitans. These bacteria have been associated with infected implants, as well as other frequent hard tissue related infections. Extracts of different compositions of MPC had bactericidal or bacteriostatic properties against the three bacterial strains tested. This was associated mainly with a synergistic effect between the high osmolarity and alkaline pH of the MPC. These intrinsic antimicrobial properties make MPC preferential candidates for applications in dentistry, such as root fillers, pulp capping agents and cavity liners.
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Interfacial degradation in composite restorations challenged by multi-species biofilms. Dent Mater 2013. [DOI: 10.1016/j.dental.2013.08.151] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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A reproducible oral microcosm biofilm model for testing dental materials. J Appl Microbiol 2012; 113:1540-53. [PMID: 22925110 DOI: 10.1111/j.1365-2672.2012.05439.x] [Citation(s) in RCA: 86] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2012] [Revised: 07/31/2012] [Accepted: 08/15/2012] [Indexed: 12/28/2022]
Abstract
AIMS Most studies of biofilm effects on dental materials use single-species biofilms, or consortia. Microcosm biofilms grown directly from saliva or plaque are much more diverse, but difficult to characterize. We used the Human Oral Microbial Identification Microarray (HOMIM) to validate a reproducible oral microcosm model. METHODS AND RESULTS Saliva and dental plaque were collected from adults and children. Hydroxyapatite and dental composite discs were inoculated with either saliva or plaque, and microcosm biofilms were grown in a CDC biofilm reactor. In later experiments, the reactor was pulsed with sucrose. DNA from inoculums and microcosms was analysed by HOMIM for 272 species. Microcosms included about 60% of species from the original inoculum. Biofilms grown on hydroxyapatite and composites were extremely similar. Sucrose pulsing decreased diversity and pH, but increased the abundance of Streptococcus and Veillonella. Biofilms from the same donor, grown at different times, clustered together. CONCLUSIONS This model produced reproducible microcosm biofilms that were representative of the oral microbiota. Sucrose induced changes associated with dental caries. SIGNIFICANCE AND IMPACT OF THE STUDY This is the first use of HOMIM to validate an oral microcosm model that can be used to study the effects of complex biofilms on dental materials.
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Quantifying dental biofilm growth using cross-polarization optical coherence tomography. Lett Appl Microbiol 2012; 54:537-42. [PMID: 22435929 DOI: 10.1111/j.1472-765x.2012.03243.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
AIMS Quantifying the ex vivo growth of complex multispecies dental biofilms using cross-polarization 1310-nm optical coherence tomography (CP-OCT) system was investigated. METHODS AND RESULTS Bacterial microcosms, which were derived from plaque samples of paediatric subjects, were incubated in a biofilm reactor system containing discs of different dental materials for 72 h with daily sucrose pulsing (5×). CP-OCT analysis of biofilm mass was validated with crystal violet (CV) assays at various growth stages of these complex biofilms. CP-OCT was able to filter out the back-reflected signals of water layers in the hydrated biofilm and allowed for direct biofilm quantification. The overall depth-resolved scattering intensity of the biofilm showed very strong positive correlation with CV assay quantification (Spearman's ρ = 0.92) during the growth phase of the biofilm. CONCLUSION CP-OCT was able to quantify the mass of the biofilm by measuring the overall depth-resolved scattering of the biofilm. SIGNIFICANCE AND IMPACT OF THE STUDY CP-OCT has the ability to nondestructively monitor biofilm growth and elucidate the growth characteristics of these microcosms on different dental material compositions.
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Specific volume and compressibility measurements of tomato paste at moderately high pressure as a function of temperature. J FOOD ENG 2011. [DOI: 10.1016/j.jfoodeng.2010.10.021] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Effect of blasting treatment and Fn coating on MG63 adhesion and differentiation on titanium: a gene expression study using real-time RT-PCR. JOURNAL OF MATERIALS SCIENCE. MATERIALS IN MEDICINE 2011; 22:617-627. [PMID: 21258846 DOI: 10.1007/s10856-011-4229-3] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2009] [Accepted: 01/04/2011] [Indexed: 05/30/2023]
Abstract
Biomaterial surface properties, via alterations in the adsorbed protein layer, and the presence of specific functional groups can influence integrin binding specificity, thereby modulating cell adhesion and differentiation processes. The adsorption of fibronectin, a protein directly involved in osteoblast adhesion to the extracellular matrix, has been related to different physical and chemical properties of biomaterial surfaces. This study used blasting particles of different sizes and chemical compositions to evaluate the response of MG63 osteoblast-like cells on smooth and blasted titanium surfaces, with and without fibronectin coatings, by means of real-time reverse transcription-polymerase chain reaction (qRT-PCR) assays. This response included (a) expression of the α(5), α(v) and α(3) integrin subunits, which can bind to fibronectin through the RGD binding site, and (b) expression of alkaline phosphatase (ALP) and osteocalcin (OC) as cell-differentiation markers. ALP activity and synthesis of OC were also tested. Cells on SiC-blasted Ti surfaces expressed higher amounts of the α(5) mRNA gene than cells on Al(2)O(3)-blasted Ti surfaces. This may be related to the fact that SiC-blasted surfaces adsorbed higher amounts of fibronectin due to their higher surface free energy and therefore provided a higher number of specific cell-binding sites. Fn-coated Ti surfaces decreased α(5) mRNA gene expression, by favoring the formation of other integrins involved in adhesion over α(5)β(1). The changes in α(5) mRNA expression induced by the presence of fibronectin coatings may moreover influence the osteoblast differentiation pathway, as fibronectin coatings on Ti surfaces also decreased both ALP mRNA expression and ALP activity after 14 and 21 days of cell culture.
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Variation of roughness and adhesion strength of deposited apatite layers on titanium dental implants. MATERIALS SCIENCE & ENGINEERING. C, MATERIALS FOR BIOLOGICAL APPLICATIONS 2011. [DOI: 10.1016/j.msec.2010.09.018] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Comparing Locomotion With Lever-press Travel In An Operant Simulation Of Foraging. J Exp Anal Behav 2010; 68:177-92. [PMID: 16812854 PMCID: PMC1284625 DOI: 10.1901/jeab.1997.68-177] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Experimental determination of the amount of ice instantaneously formed in high-pressure shift freezing. J FOOD ENG 2009. [DOI: 10.1016/j.jfoodeng.2009.06.036] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Abstract
Commercially pure titanium (cp Ti) dental implants have been widely and successfully used with high rates of clinical success in normal situations. However, there is still a lack of reliable synthetic materials to be used either a) when immediate loading of the implant is desired or b) when bone presents compromised conditions due to trauma, infection, systemic disease and/or lack of significant bone volume. Our group has aimed the development of biomimetic strategies of surface modification to obtain metallic implants with osteostimulative capabilities. These surface modifications will provide implants with a rapid rate of newly-formed bone growth and with ossecoalescence, i.e., direct chemical contact with the surrounding tissues. Consequently, the biomimetically-modified implants will be reliably used on those more demanding clinical situations. cp Ti surfaces treated to obtain a combination of an optimal random surface topography (in the micro and nanolevels) with a chemical modification of the naturally-formed titania layer have been proved bioactive. These rough and bioactive surfaces nucleate and grow a homogeneous hydroxyapatite layer both in vitro and in vivo. They stimulate the osteoblasts differentiation and trigger a rapid bone formation that mechanically fixes implants under immediate-loading conditions. A simple process using silane chemistry has been proved specific, rapid, and reliable to covalently immobilize biomolecules on c.p. Ti surfaces. This methodology can be used to develop biofunctionalized implant surfaces with different or combined bioactivities. The biofunctional molecules can be biopolymers, proteins, growth factors, and synthetic peptides specifically designed to be attached to the surface. The bioactive properties of the molecules designed and used can be mineral growing and nucleation, osteoblast differentiation (bone regeneration), fibroblasts differentiation (biological sealing), antibiotic,… Specifically, we have obtained mechanically and thermochemically stable coatings made of recombinant elastin-like biopolymers. The biopolymers bear either a) the RGDS peptide, which is a highly-specific cell-adhesion motif present in proteins of the extracellular matrix for different tissues including bone, or b) an acidic peptide sequence derived from statherin, a protein present in saliva with high affinity for calcium-phosphates and with a leading role in the remineralization processes of the hard tissues forming our teeth. Two different biomimetic strategies have been successfully developed combining topographical modification, inorganic treatments and/or biofunctionalization for improving bioactive integrative properties of c.p. Ti implants.
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Analyse descriptive des patients de 5 consultations sans rendez-vous avec PASS intégrée à l’AP–HP. Rev Med Interne 2009. [DOI: 10.1016/j.revmed.2009.03.069] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Prediction of ice content in biological model solutions when frozen under high pressure. Biotechnol Prog 2009; 25:454-60. [DOI: 10.1002/btpr.103] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Abstract
A new oxidation treatment (OT) on NiTi shape memory alloys was developed in a previous work. This OT treatment significantly decreases Ni ion release into the exterior medium, and therefore is thought to be beneficial for NiTi cytocompatibility. As to confirm this expectation, the in vitro response of MG63 osteoblast-like cells cultured on untreated and oxidized NiTi surfaces was studied. An adhesion test at 1, 4, and 8 h of incubation was performed. Statistical differences were evidenced at 1 h of adhesion depending on the surface treatment and chemical composition of the substrate. However, at larger times of study, there were no statistically significant differences between untreated and oxidized surfaces. The proliferation test (until 9 days) showed that untreated and oxidized NiTi surfaces are not cytotoxic for MG63 cells. The differences of adhesion at short times did not affect the proliferation of MG63 cells. However, after 48 h of stimulation with ascorbic acid and dexamethasone, the MG63 cells cultured on oxidized surfaces showed higher alkaline phosphatase activity and osteocalcin levels. The improvement of osteoblast differentiation due to OT treatment could accelerate bone formation, and, therefore, could allow earlier loading of NiTi devices used in dental and orthopedic applications.
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Acceleration of apatite nucleation on microrough bioactive titanium for bone-replacing implants. J Biomed Mater Res A 2007; 82:521-9. [PMID: 17295245 DOI: 10.1002/jbm.a.31164] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The viability of a new two-step method for obtaining bioactive microrough titanium surfaces for bone replacing implants has been evaluated. The method consists of (1) Grit blasting on titanium surface to roughen it; and (2) Thermo-chemical treating to obtain a bioactive surface with bone-bonding ability by means of nucleating and growing an apatite layer on the treated surface of the metal. The aim of this work is to evaluate the effect of surface roughness and chemical composition of the grit-blasting particles on the ability of the surfaces of nucleating and growing a homogeneous apatite layer. The determination and kinetics of the nucleation and growing of the apatite layer on the surfaces has mainly been studied with environmental scanning electron microscopy (ESEM) and grazing-incidence X-ray diffractometry. The results show that Al(2)O(3)-blasted and thermochemically-treated titanium surfaces accelerates nucleation of the apatite, whereas SiC-blasted and thermochemically-treated titanium surfaces inhibits apatite nucleation, compared with the well studied polished and thermochemically-treated titanium surfaces. The acceleration of the apatite nucleation on the Al(2)O(3)-blasted microrough titanium surfaces is because concave parts of the microroughness that are obtained during grit blasting provides to the rough and bioactive surfaces with a chemical- and electrostatic-favored situation for apatite nucleation. This consists of a high density of surface negative charges (also assisted by the nanoroughness of the surface obtained after the thermochemical treatment) and an increased concentration of the Ca(2+)-ions of the fluid, which have a limited mobility at the bottom of the concave parts.
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03 Factores de riesgo de daño renal asociado a pielonefritis en 175 niños. An Pediatr (Barc) 2007. [DOI: 10.1016/s1695-4033(07)70761-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
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32 Tumoración vesical en la edad pediátrica. An Pediatr (Barc) 2007. [DOI: 10.1016/s1695-4033(07)70790-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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New oxidation treatment of NiTi shape memory alloys to obtain Ni-free surfaces and to improve biocompatibility. J Biomed Mater Res B Appl Biomater 2006; 77:249-56. [PMID: 16245290 DOI: 10.1002/jbm.b.30441] [Citation(s) in RCA: 114] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Various oxidation treatments were applied to nearly equiatomic NiTi alloys so as to form a Ni-free protective oxide on the surface. Sample surfaces were analyzed by X-ray Photoelectron Spectroscopy, and NiTi transformation temperatures were determined by differential scanning calorimetry (DSC) before and after the surface treatment. An ion release experiment was carried out up to one month of immersion in SBF for both oxidized and untreated surfaces. The results show that oxidation treatment in a low-oxygen pressure atmosphere leads to a high surface Ti/Ni ratio, a very low Ni surface concentration and a thick oxide layer. This oxidation treatment does not significantly affect the shape memory properties of the alloy. Moreover, the oxide formed significantly decreases Ni release into exterior medium comparing with untreated surfaces. As a consequence, this new oxidation treatment could be of great interest for biomedical applications, as it could minimize sensitization and allergies and improve biocompatibility and corrosion resistance of NiTi shape memory alloys.
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Development of a Biodegradable Composite Scaffold for Bone Tissue Engineering: Physicochemical, Topographical, Mechanical, Degradation, and Biological Properties. ORDERED POLYMERIC NANOSTRUCTURES AT SURFACES 2006. [DOI: 10.1007/12_068] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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Surface characterization of completely degradable composite scaffolds. JOURNAL OF MATERIALS SCIENCE. MATERIALS IN MEDICINE 2005; 16:1125-30. [PMID: 16362211 DOI: 10.1007/s10856-005-4717-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2005] [Accepted: 07/26/2005] [Indexed: 05/05/2023]
Abstract
The goal of this study was to characterise the surface properties of completely degradable composite, polylactic acid and calcium phosphate glass, scaffolds. The composite scaffolds are made by solvent casting or phase-separation, using chloroform and dioxane as a solvent respectively. The surface properties were measured on composite films which were made using the same procedure as for the three-dimensional (3D) scaffolds without the pore-creating step. The surface morphology, roughness, wettability and protein adsorption capacity of the films was measured before and after sterilisation with ethylene oxide. The results reveal the influence of solvent type, glass weight content and sterilisation on the wettability, surface energy and protein adsorption capacity of the materials. The addition of glass particles increase the hydrophylicity, roughness and protein adsorption capacity of the surface. This effect, however, depends on the extent of the coating of the glass particles by the polymer film, which is much higher for dioxane films than for chloroform films. This information can be used to interpret and understand the biological behaviour of the 3D scaffolds made of this composite materials.
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[Use of oral anticholinergic therapy in children under 1 years of age with high risk bladder]. CIRUGIA PEDIATRICA : ORGANO OFICIAL DE LA SOCIEDAD ESPANOLA DE CIRUGIA PEDIATRICA 2005; 18:3-7. [PMID: 15901100] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
THE AIM To assess the effectiveness and safety of the treatment with oral anticholinergic agents (Oxybutin clorure) in patients under 1 year old, and who aree carriers of high risk bladder secondary to neurological illness as well as no neurological one. MATERIAL AND METHODS Since 1989, we have indicated treatment with anticholinergic agents to 16 patients: 9 patients had neurogenic bladder secondary to: myelomeningocele (n=7) and sacrocoxigeal teratoma (n=2). Others 7 patients had non neurogenic bladder secondary to: posterior urethral valvulas (n=1), valvula-like syndrome (n=4), post-surgery of neonatal giant bladder diverticulum (n=1) and Prune-Belly syndrome (n=1). The urodinamic study was performed during the first six months of life, being "high risk bladder" defined according to the parameters of compliance vesical and pressure of leak at point (PER). Five of the patients showed neonatal cronic renal failure (CRF), who were treated by cutaneus temporary derivation. All patients at treatment with anticholinergic agents at a 0.2 mg/kg/day dose was established; other early adjunctive treatment prior to the closure of the urinary derivation in children with CRF(n=5); or as a part of the conservative treatment (n=3), alone or associate to intermittent bladder catheterization (IBC) (n=8). During the treatment with anticholinergic agents, the cardiac frequency was controlled by EKG registration in 6 patients, being the rest of the children clinicaly controled (skin colour, mouth dryness, cardiac frequency and intestinal function). RESULTS In all the cases, the minimum duration of the treatment was one year, until the functional stabilization of the urinary tract. It is to underline the absence of secondary complications which would have caused the suspension or the reduction of the treatment at long term. Conventional studies of urologicals image and urodinamic studies, showed the stabilization of the urinary tract and also the preservation of kidney function and not only was demonstrated in those patients with oral anticholinergic agent as their unique treatment, but also in those patients who had previously been derivated. The previous vesical stabilization allowed the optimum result of subsequent corrective surgeries in five patients (ureteroneocystostomy and vesiscotomy clousure. In cases with previous derivation, the treatment with oral anticholinergic agents made easier vesicostomic clousure in the forth quarter of the first year old wih the maintenance of the vesical stability. CONCLUSIONS The use of oral anticholinergic agents at a dose of 0.2 mg/kg/day, has resulted to be safe as well as effective in the treatment of high risk bladder in infancy those with less than one year of life. In those patients with serious dysplasia by reflux, it contributes to the preservation of kidney function, it makes easier the early desderivation and it also stabilizes in a functional way the bladder as a previous step to subsequent reconstructive surgeries.
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Calcium phosphate bone substitutes. THE MEDICAL JOURNAL OF MALAYSIA 2004; 59 Suppl B:65-6. [PMID: 15468821] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 04/30/2023]
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Food allergy to wheat: identification of immunogloglin E and immunoglobulin G-binding proteins with sequential extracts and purified proteins from wheat flour. Clin Exp Allergy 2003; 33:962-70. [PMID: 12859454 DOI: 10.1046/j.1365-2222.2003.01592.x] [Citation(s) in RCA: 102] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
BACKGROUND Cereal-associated allergy is particularly considered a serious problem, because cereals are essential in our daily diet. Wheat proteins are classified into albumins, globulins and prolamins (insoluble gliadins and glutenins). OBJECTIVES Our objectives were to study the involvement in food allergy to wheat of these different protein types by using purified fractions and to identify those binding IgE and IgG antibodies. METHODS Sera were obtained from 28 patients with food allergy to wheat. Albumins/globulins, gliadins and glutenins were obtained by sequential extraction based on differential solubility; alpha-, beta-, gamma- and omega-gliadins and low molecular weight (LMW) and high molecular weight (HMW) glutenin subunits were purified by chromatography. IgE binding to these extracts and fractions were analysed by radioallergosorbent test (RAST), and immunoblotting; IgG binding was detected by enzyme-linked immunosorbent assay (ELISA). RESULTS In RAST, 60% of sera were shown to have specific IgE antibodies against alpha-, beta-gliadins and LMW glutenin subunits, 55% to gamma-gliadins, 48% to omega-gliadins and 26% to HMW glutenins. Immunoblotting analysis confirmed results obtained in RAST concerning LMW and HMW glutenin subunits and showed that 67% of patients have IgE antibodies to the albumin/globulin fraction. CONCLUSION Results obtained in the different tests showed common features and in agreement with other studies indicated the presence of numerous allergens in food allergy to wheat; alpha-, beta-, gamma- and omega-gliadins, LMW glutenin subunits and some water/salt-soluble proteins appeared as major IgE binding allergens, whereas HMW glutenins were only minor allergens. The same type of antigenic profile against gliadins and glutenins was observed with IgG antibodies. Important sequence or structural homologies between the various gliadins and LMW glutenin subunits could certainly explain similarity of IgE binding to these proteins.
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Human-osteoblast proliferation and differentiation on grit-blasted and bioactive titanium for dental applications. JOURNAL OF MATERIALS SCIENCE. MATERIALS IN MEDICINE 2002; 13:1105-1111. [PMID: 15348651 DOI: 10.1023/a:1021173500990] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Physico-chemical and topographical surface quality of commercially pure titanium (c.p. Ti) dental implants is one of the most influencing factors in the improvement of their osseointegration. In this sense, previously, a two-step method (2S) for obtaining bioactive blasted-rough titanium surfaces was developed for improving short-term (due to its bioactivity) and long-term (due to its roughness) osseointegration. This 2S-method consists of: (1) Grit blasting on titanium surface in order to roughen it, and (2) thermo-chemical (TCh) treatment in order to obtain a bioactive surface with bone-bonding ability. The aim of the present work is to evaluate the in vitro human-osteoblast response (proliferation, differentiation - ALP activity- and cell morphology-studied by environmental scanning electron microscopy) of rough c.p. Ti (grit blasted), bioactive c.p. Ti (thermo-chemically treated) and rough-bioactive c.p. Ti (2S-treated). Different grit materials (Al(2)O(3) and SiC) have been used in order to investigate their influence. The results showed that cell adhesion was statistically higher for the rough and bioactive surfaces, whatever the grit used. Cells proliferated very well on all the c.p. Ti surfaces. If comparing groups with and without TCh (all other treatments being equal) the ALP was always higher in the groups with TCh, indicating stimulation of osteoblast differentiation because of TCh, more significantly in the groups that were first blasted. Those ALP results were accompanied by a decrease in the value of proliferation, which shows the good behavior of the cells. This results suggest that a rough and bioactive-titanium surface obtained by 2S-treatment enhances adhesion and differentiation activity of human osteoblasts cells.
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Abstract
Some metallic materials, such as pure titanium, Ti-6Al-4V, are used for dental and orthopedic implants under load-bearing conditions. However, they do not form a chemical bond with bone, which would achieve a good implant-bone fixation in service. In recent works, it has been demonstrated that an in vitro, chemically deposited, bone-like apatite layer with bone-bonding ability could be induced on a titanium surface. By reproducing that chemical procedure, in this work, a dense bone-like apatite layer was formed on the surface of the titanium in simulated body fluid. In addition, the different steps and kinetics of the layer-formation have been studied, because the observation of the samples in the wet state by means of the environmental scanning electron microscope has allowed the observation in situ of the apatite deposition process over a number of days. One of the most important features of the present study is that it can be carried out on a single titanium sample and the process is not interrupted at any stage. One of the main drawbacks of this chemical method is that the samples covered with apatite are susceptible to contamination by bacteria. The behavior of different types of antibiotics used to avoid this contamination has also been studied using the environmental scanning electron microscope. Finally, osteoblast cells have been cultured on the apatite-coated titanium samples to assess their biocompatibility.
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Abstract
The effect that three different radiopacifying agents, two of them inorganic (BaSO4, ZrO2) and one organic (an iodine containing monomer, IHQM) have on the static and dynamic mechanical properties of acrylic bone cements was studied. Compressive and tensile strength, fracture toughness and fatigue crack propagation were evaluated. The effect of the inorganic fillers depends on their size and morphology. In relation to the radiolucent cement, the addition of zirconium dioxide improved significantly the tensile strength, the fracture toughness and the fatigue crack propagation resistance. In contrast, the addition of barium sulphate produced a decrease of the tensile strength, but did not affect the fracture toughness and improved the crack propagation resistance. When the iodine containing monomer was used, although the tensile strength and the fracture toughness increased, the fatigue crack propagation resistance remained as low as it was for the radiolucent cement.
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Hydroxyapatite ceramic bodies with tailored mechanical properties for different applications. JOURNAL OF BIOMEDICAL MATERIALS RESEARCH 2002; 60:159-66. [PMID: 11835171 DOI: 10.1002/jbm.1286] [Citation(s) in RCA: 77] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
A perfect control on the final ceramic features will enable the research/clinical community to spread the use of calcium phosphate ceramic bodies to a large number of applications and/or requirements. The mechanical properties of hydroxyapatite ceramic bodies manufactured by different techniques and with different porosities is presented. The flexural strength, hardness, fracture toughness, surface roughness, and their evolution after immersion in SBF are studied. An increase of the mechanical properties with density is observed. The factors governing these results are analyzed. The increase of the porosity percentage of the bodies results in an increase on the surface roughness. The degradation studies show that the HA ceramics keep their integrity and mechanical properties under physiological conditions during the soaking time studied. The OHAp ceramic bodies with controlled porosity could be appropriated for hard tissue substitution or as a carriers for controlled delivery of drugs or as scaffolds for tissue engineering.
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[Allergenicity of wheat flour]. ALLERGIE ET IMMUNOLOGIE 2002; 34:98-9. [PMID: 12012796] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/25/2023]
Abstract
Food allergy to wheat flour is a pathology that is found less frequently than coeliac disease or respiratory allergy to flour; it seems however to be a constant argument. Our study used a panel of 28 patients diagnosed with food allergy to wheat flour. Our objective was to characterise the reactivity of type IgE and IgG antibodies of these patients with regard to the different classes of proteins of wheat flour so as to establish an antigenic profile of the allergens of wheat in the framework of food allergy to flour. Our results show the implication of different classes of wheat proteins and notably the major reserve proteins (gliadins and glutens) in food allergy.
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Alveolar ridge widening by distraction osteogenesis: a case report. PRACTICAL PROCEDURES & AESTHETIC DENTISTRY : PPAD 2001; 13:663-8; quiz 670. [PMID: 11799798] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/23/2023]
Abstract
Alveolar width deficiencies have generally been corrected by guided tissue regeneration or bone augmentation with and without membranes. The use of distraction osteogenesis is proposed for the correction of horizontal alveolar width defects. In this case report, horizontal bone generation by distraction osteogenesis was achieved prior to implant placement. Following implant restoration, favorable bone response was observed after two years of function. Distraction osteogenesis to widen the alveolus may prove to be a clinically useful treatment option in selected cases.
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Tilted implants as an alternative to maxillary sinus grafting: a clinical, radiologic, and periotest study. Clin Implant Dent Relat Res 2001; 3:39-49. [PMID: 11441542 DOI: 10.1111/j.1708-8208.2001.tb00127.x] [Citation(s) in RCA: 168] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
BACKGROUND Owing to mechanical and anatomic difficulties, implant treatment in the atrophic maxilla represents a challenge. The maxillary sinus floor augmentation procedure is still not universally accepted because of its complexity and its unpredictability. PURPOSE In this study, a combination of tilted and axial implants was used in patients with severely resorbed posterior maxillae as an alternative to sinus grafting. MATERIALS AND METHODS Twenty-five patients were rehabilitated with 29 fixed partial prostheses supported by 101 Brånemark System implants. Fifty-nine implants were installed in an axial and 42 in a tilted direction. The average follow-up period was 37 months (range: 21-87 mo post loading). RESULTS After 5 years, the implant cumulative success rate was 95.2% (survival: rate 100%) for the tilted implants and 91.3% (survival rate: 96.5%) for the axial implants, and the prosthesis survival rate was 100%. At the fifth year, the average marginal bone loss was 1.21 mm for the tilted implants and 0.92 mm for the axial ones. The mean Periotest values (PTV) at loading time were -2.62 and -3.57, and after 5 years the PTVs were -4.73 and -5.00 for the tilted and the axial implants, respectively. During the follow-up, all prostheses but two were mechanically stable, retightening of 18 abutment screws and of 5 gold screws in 14 prostheses was done, and fracture of two abutment screws and two occlusal surfaces was experienced. CONCLUSIONS Results indicate that the use of tilted implants is an effective and safe alternative to maxillary sinus floor augmentation procedures.
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Deficiency or inhibition of Gas6 causes platelet dysfunction and protects mice against thrombosis. Nat Med 2001; 7:215-21. [PMID: 11175853 DOI: 10.1038/84667] [Citation(s) in RCA: 342] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The growth arrest-specific gene 6 product (Gas6) is a secreted protein related to the anticoagulant protein S but its role in hemostasis is unknown. Here we show that inactivation of the Gas6 gene prevented venous and arterial thrombosis in mice, and protected against fatal collagen/epinephrine-induced thrombo embolism. Gas6-/- mice did not, however, suffer spontaneous bleeding and had normal bleeding after tail clipping. In addition, we found that Gas6 antibodies inhibited platelet aggregation in vitro and protected mice against fatal thrombo embolism without causing bleeding in vivo. Gas6 amplified platelet aggregation and secretion in response to known agonists. Platelet dysfunction in Gas6-/- mice resembled that of patients with platelet signaling transduction defects. Thus, Gas6 is a platelet-response amplifier that plays a significant role in thrombosis. These findings warrant further evaluation of the possible therapeutic use of Gas6 inhibition for prevention of thrombosis.
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[Allergy to cypress pollen: preparation of a reference and standardization extract in vivo]. ALLERGIE ET IMMUNOLOGIE 2000; 32:101-3. [PMID: 10815236] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
Abstract
Development of Cypress allergy frequency led to the standardization of commercial cypress extract used for diagnosis and immunotherapy. Previous in vitro studies on two cypress pollen species (Cupressus sempervirens and Cupressus arizonica) allowed us to produce an allergenic solution composed by a mixture of both extracts for in vivo standardization. Dilutions of this allergenic solution were tested by prick-test on 44 patients with clinical allergy to cypress pollen to define the dilution that corresponds to a 6 mm wheal conformed to the definition of 100 IR. The mixture of the two major species found in France is justified by the in vitro study results. Extracts revealed complementary allergenic composition: Cup sempervirens showed a wider diversity of allergens whereas Cup arizonica showed a higher content of the major 43 kDa allergen. Thus, according to in vivo analysis, we are able to produce a standardized extract of Cypress pollen expressed in IR.
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Improvement of the mechanical properties of acrylic bone cements by substitution of the radio-opaque agent. JOURNAL OF MATERIALS SCIENCE. MATERIALS IN MEDICINE 1999; 10:733-737. [PMID: 15347942 DOI: 10.1023/a:1008979207968] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Acrylic bone cements become radio-opaque by the addition of an inorganic compound, commonly BaSO4 or ZrO2. However, the use of these additives has some negative effects such as loss of mechanical properties, risk of release and bone resorption. The use of the monomer 2,5-diiodo-8-quinolyl methacrylate (IHQM), which shows adequate polymerization and radio-opacity properties, is proposed as a new X-ray opaque, methacrylate iodine-containing agent. The aim of this study is to determine the effect of this new radio-opaque agent on the mechanical properties of acrylic bone cements. The addition of the iodine-containing methacrylate provides a statistically significant increase in the tensile strength, fracture toughness and ductility, with respect to the barium sulphate-containing cement. This effect can be attributed to the fact that the use of a radio-opaque monomer eliminates the porosity associated with the barium sulfate particles, which show no adhesion to the matrix. However, some reinforcing effect must also be attributed to the iodine-containing monomer, since the tensile and fracture toughness values reached are even higher than those shown by the radiolucent cement.
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Use of 5-mm-diameter implants: Periotest values related to a clinical and radiographic evaluation. Clin Oral Implants Res 1998; 9:398-406. [PMID: 11429941 DOI: 10.1034/j.1600-0501.1996.090605.x] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
A modified design of the original Brånemark implant consisting of a cp. Titanium 5.0-mm-diameter self-tapping implant threaded up to the marginal platform has been proposed for specific indications. From February 1992 to November 1995, a total of 185 machined screw implants (Nobel Biocare, Gothenburg, Sweden) were installed in 45 patients to withstand 58 prostheses. Of these, 91 were 3.75-mm diameter and 94 were 5.0-mm wide. Most of the implants were placed in type B and C bone quantity and type 2 and 3 bone quality. A retrospective evaluation with regard to indications, marginal bone remodelling, Periotest values (PTv) and survival rate is presented. PTv and radiographic measurements were made at abutment connection and repeated 3, 6 and 12 months later and thereafter every year. The follow-up ranged from 16 to 55 months (mean 32.9 months) post-loading. Three patients with 8 5.0-mm implants dropped-out of the study at different stages. Out of the wide implants, 1 was expelled during the healing period; 3 were found mobile at the abutment connection; 1 lost its osseointegration suddenly after 2 years of function; 4 belonging to 1 patient did not meet the success criteria due to continuous marginal bone loss. The cumulative success rate of 5.0-mm implants (CSR) after 1 year of function was 97.2% for upper jaws and 88.4% in mandibles, whereas the CSR in maxilla after 48 months was 97.2% and 83.4% in mandibles. The obtained PTv from 5.0-mm-wide fixtures in maxilla and mandibles were respectively 1.1 and 0.6 units lower than those obtained PTv for 3.75-mm-diameter implants in the same patients. The hypothesis that there are differences in the damping capacity of the bone surrounding a 5.0-mm-wide implant compared to the 3.75-mm-diameter implant is supported by the PTv results.
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Recycling of Polyolefins: Part 2: Blends of Several Polymers. JOURNAL OF MACROMOLECULAR SCIENCE PART A-PURE AND APPLIED CHEMISTRY 1998. [DOI: 10.1080/10601329808002125] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Relationship between contact time measurements and PTV values when using the Periotest to measure implant stability. INT J PROSTHODONT 1998; 11:269-75. [PMID: 9728122] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
PURPOSE The Periotest is an electronic instrument that has been advocated for the measurement of implant stability and osseointegration. The aims of this investigation were to establish the relationship between contact time and PTV values when the Periotest was used to assess implants in vivo and in vitro, and to investigate the influence of the striking height of the Periotest handpiece and the length of implant abutment. MATERIALS AND METHODS The accelerometer signal from a Periotest was captured and compared with the resulting PTV value. In vitro measurements of PTV and contract time were performed on a 3-mm abutment that had been attached to a 15-mm implant luted into an aluminium block, and were repeated on a patient in vivo. further measurements were made of the abutments of six implants in turn in the maxilla of the same patient. The standard abutment lengths on the implants were 3, 4 (x 2), 5.5 (x 2), and 7 mm. RESULTS The results indicated that there was a linear relationship between contact time and PTV value for implants measured in vitro and in vivo. Greater scatter of the in vivo data was attributed to test and patient variables including striking position, distance, and damping as a result of the presence of soft tissue. There was a linear relationship between the PTV value and the striking height for implant measurements in vivo and in vitro. CONCLUSION It can be concluded that the sensitivity of the Periotest to clinical variables including striking heights and handpiece angulation limit the application of the instrument as a clinical diagnostic aid to measure implant stability.
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D-dimères: peuvent-ils modifier la durée du traitement anticoagulant de la maladie veineuse thromboembolique ? Rev Med Interne 1997. [DOI: 10.1016/s0248-8663(97)80308-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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The use of the Periotest value as the initial success criteria of an implant: 8-year report. INT J PERIODONT REST 1997; 17:150-61. [PMID: 9497709] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Osseointegration is a histometric process that occurs gradually over a period of time. The load that an implant is able to bear depends upon, among other parameters, the quality of the bone-implant contact. For 8 years the damping capacity of 1,182 Brånemark implants inserted consecutively in 315 patients was measured using the Periotest method. The following clinical observations were made: (1) a relationship was found between implants with a specific Periotest value range that, at the moment of the transepithelial connection, were considered to be clinically stable, asymptomatic, and whose radiograph image was not radiolucent; (2) a relationship was found between clinically nonintegrated implants with a different Periotest value range; (3) variations in the Periotest value were related to the type of bone in which the implant was placed; (4) a small percentage of borderline implants with a Periotest value between the osseointegrated and the nonosseointegrated Periotest values was detected; (5) the percentage of secondary failures was related to an initial Periotest value corresponding to a borderline implant; (6) the healing time of each implant was individualized in accordance with the successively obtained Periotest value; (7) the load and the design of the prosthesis were individualized; (8) early detection of failing implants before fabrication of prostheses is possible; (9) communication was improved between the surgeon and the prosthodontist; and (10) variations in Periotest value were related to bone remodeling. The sensitivity of the principal clinical test in evaluating osseointegration is discussed regarding the moment of its application. The use of Periotest values as an initial success criteria of an implant is proposed.
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