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Eusufzai SZ, Barman A, Jamayet NB, Ahmad WMAW, Mahdi SS, Sheikh Z, Daood U. Effects of Riboflavin Collagen Crosslinker on Dentin Adhesive Bonding Efficiency: A Systematic Review and Meta-Analysis. MATERIALS (BASEL, SWITZERLAND) 2023; 16:1701. [PMID: 36837334 PMCID: PMC9963098 DOI: 10.3390/ma16041701] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/19/2022] [Revised: 02/06/2023] [Accepted: 02/07/2023] [Indexed: 06/18/2023]
Abstract
The aim of this study was to evaluate published data regarding riboflavin (RF) as a cross-linker for improved adhesive bond strength to dentin and to analyze previous studies for optimal concentration of riboflavin range suitable for dentin bond. Saliva and distilled water were used as storage media and aging time was 24 h and 6 months. Results of meta-analysis were synthesized using a statistical method of inverse variance in random effects with a 95% Confidence Interval (CI). Cochrane review manager 5.4.1 was used to determine results of the meta-analysis. In total, 3172 articles were found from search databases "PubMed", "Scopus", and "Google Scholar". Six of the fifteen studies were eligible for meta-analysis. Micro tensile strength shows significant improvement with the addition of riboflavin (p < 0.05) compared to without the addition of riboflavin from with 95% CI. A significant difference has been found in micro tensile bond strength between use of the riboflavin cross-linker and without use of the riboflavin crosslinker in the dentin adhesive system. With a 95% confidence interval (CI), the I2 for micro tensile strength was 89% with strong heterogeneity, Chi2 = 44.76, df = 5 (p < 0.00001), and overall effect size is Z = 2.22 (p = 0.03) after immediate aging. Chiang et al. 2013 shows maximum mean differences which is 38.50 [17.93-59.07]. After 6 months of aging in distilled water or artificial saliva micro tensile bond strength has been increased with the addition of riboflavin (p < 0.05). It can be clearly seen that pooled effect and 95% CI did not cross the line of no effect. With a 95% confidence interval (CI), the I2 for micro tensile strength was 96% with strong heterogeneity, Chi2 = 117.56, df = 5 (p < 0.00001), and overall effect size is Z = 2.30 (p = 0.02). Subgroup analysis proved a similar effect of distilled water and artificial saliva as storage media on micro tensile bond strength after incorporating riboflavin as a collagen crosslinker. An artificial saliva aged forest plot also showed considerable heterogeneity with I2 = 96%; Tau2 = 257.32; Chi2 = 94.37; df = 2 (p < 0.00001); test for overall effect, Z = 1.06 (p = 0.29). Riboflavin prior to or with bonding is recommended to improve the bonding of different adhesive systems.
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Affiliation(s)
- Sumaiya Zabin Eusufzai
- School of Dental Sciences, Health Campus, Universiti Sains Malaysia, Kubang Kerian, Kota Bharu 16150, Malaysia
| | - Aparna Barman
- School of Dental Sciences, Health Campus, Universiti Sains Malaysia, Kubang Kerian, Kota Bharu 16150, Malaysia
| | - Nafij Bin Jamayet
- Restorative Dentistry Division, School of Dentistry, International Medical University Kuala Lumpur, 126, Jalan Jalil Perkasa 19, Wilayah Persekutuan Kuala Lumpur, Bukit Jalil, Kuala Lumpur 57000, Malaysia
| | - Wan Muhamad Amir W Ahmad
- School of Dental Sciences, Health Campus, Universiti Sains Malaysia, Kubang Kerian, Kota Bharu 16150, Malaysia
| | - Syed Sarosh Mahdi
- Division of Clinical Oral Health Sciences, School of Dentistry, International Medical University, Kuala Lumpur 57000, Malaysia
- Faculty of Dentistry, Dalhousie University, 5981 University Ave, Halifax, NS B3H 1W2, Canada
| | - Zeeshan Sheikh
- Faculty of Dentistry, Dalhousie University, 5981 University Ave, Halifax, NS B3H 1W2, Canada
| | - Umer Daood
- Restorative Dentistry Division, School of Dentistry, International Medical University Kuala Lumpur, 126, Jalan Jalil Perkasa 19, Wilayah Persekutuan Kuala Lumpur, Bukit Jalil, Kuala Lumpur 57000, Malaysia
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Diagnosis of cracked tooth: Clinical status and research progress. JAPANESE DENTAL SCIENCE REVIEW 2022; 58:357-364. [PMID: 36425316 PMCID: PMC9678967 DOI: 10.1016/j.jdsr.2022.11.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2022] [Revised: 11/01/2022] [Accepted: 11/07/2022] [Indexed: 11/19/2022] Open
Abstract
Cracked tooth is a common dental hard tissue disease.The involvement of cracks directly affects the selection of treatment and restoration of the affected teeth.It is helpful to choose more appropriate treatment options and evaluate the prognosis of the affected tooth accurately to determine the actual involvement of the crack.However, it is often difficult to accurately and quantitatively assess the scope of cracks at present.So it is necessary to find a real method of early quantitative and non-destructive crack detection.This article reviews the current clinical detection methods and research progress of cracked tooth in order to provide a reference for finding a clinical detection method for cracked tooth.
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El-Gar YHA, Etman WM, Genaid TM, Al-Madboly LA. Potent Antibacterial and Antibiofilm Activities of a Synthetic Remineralizing Preparation of Nano-Hydroxyapatite Against Cariogenic Streptococcus mutans Using an Ex-vivo Animal Model. FRONTIERS IN DENTAL MEDICINE 2022. [DOI: 10.3389/fdmed.2022.738326] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
AimThe aim to this study is to evaluate the biocompatibility and antibiofilm actions of two nano-hydroxy apatite (NHA).MethodologyNano-hydroxy apatites are biomaterials use in direct contact with living tissues. Therefore, they should be tested for their safety beside assessment of their minimum inhibitory (MIC) and minimum bactericidal concentration (MBC) using broth microdilution method. One hundred and twenty extracted bovine incisors were collected and cleaned to ensure the absence of any defects. Enamel blocks with different size (2 × 2 × 3 mm) and (5 × 5 × 2 mm) were prepared from their labial surfaces using an isomet saw. Enamel blocks are used for detecting the suitable concentration will be used in the following experiments using energy dispersive X-ray analysis (EDX). The remaining enamel blocks divided into 5 equal groups to detect inhibitory effect against bacterial adhesion to the initial enamel caries like lesions using viable count technique beside the antibiofilm activity against mature biofilm of Streptococcus mutans (S. mutans) using confocal laser microscopy. The remaining enamel blocks were used as a representing data for detecting surface topography for each group by using the scanning electron microscopy (SEM).ResultThe data showed safety of NHA suspensions. Additionally, only NHA suspension of large nanoparticle size (NHA-LPS) had MIC of 1.25 mg/ml against S. mutans. Also, have the higher percentages of Ca and P in the enamel blocks. Furthermore, the lowest level of bacterial adhesion was recorded in (group III) treated by NHA-LPS which was non-significantly different with the positive control group V. Biofilm thickness in group IV treated with NHA-small particle size (SPS) recorded high biofilm thickness followed by group III. Interestingly, group III showed greater killing effect against mature biofilm which is slightly higher than the positive control group V. In group III, surface topography revealed very smooth enamel surface with closed pores. Accordingly, NHA-LPS suspension had antiadhesive, antibacterial, and antibiofilm effect against cariogenic S. mutans representing a promising possibility to be recommended for safe effective remineralization.
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Elboraey AN, Abo-Almaged HH, El-Ashmawy AAER, Abdou AR, Moussa AR, Emara LH, El-Masry HM, El Bassyouni GET, Ramzy MI. Biological and Mechanical Properties of Denture Base Material as a Vehicle for Novel Hydroxyapatite Nanoparticles Loaded with Drug. Adv Pharm Bull 2020; 11:86-95. [PMID: 33747855 PMCID: PMC7961227 DOI: 10.34172/apb.2021.009] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2019] [Revised: 03/22/2020] [Accepted: 04/16/2020] [Indexed: 12/24/2022] Open
Abstract
Purpose: This study aimed to evaluate the biological and mechanical properties of the poly(methyl methacrylate) (PMMA) denture base material as a vehicle incorporating novel hydroxyapatite nanoparticles (HA-NP) loaded with metronidazole (MZ) drug. Methods: HA-NP was prepared via wet-chemical-method, characterized by XRD, SEM/EDX, TEM, Fourier-transform infrared spectroscopy (FTIR), as well as the measurement of surface area and pore-size distribution. Four drug delivery formulas were prepared in the form of discs (10 x 2 mm) as follows: F1 (MZ/ HA-NP/PMMA), F2 (HA-NP/ PMMA), F3 (control-PMMA) and F4 (MZ/PMMA). Characterization of all formulas was performed using differential scanning calorimetry (DSC) and FTIR. MZ release rate, antimicrobial properties against three oral pathogens, cytotoxicity (MTT assay) and surface micro-hardness were also assessed. Statistical analysis of data was performed using one-way ANOVA test (P < 0.05). Results: DSC thermograms showed compatibility among MZ, HA-NP and PMMA along with physical stability over 6 months storage period at room temperature. FTIR spectroscopy proved the absence of any possible chemical interaction with MZ. MZ-HA-NP/PMMA formula showed relatively better drug release compared to MZ-PMMA. Both formulas showed statistically significant antimicrobial potentials against two microbial strains. MTT demonstrated reduction in cell cytotoxicity after 96 hours with the least value for HA-NP. Surface micro-hardness revealed non-significant reduction compared with the control PMMA. Conclusion: A novel biocompatible drug nanocarrier (HA-NP) was developed and incorporated in PMMA denture base material as a vehicle to allow prolonged sustained drug release to manage oral infections.
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Affiliation(s)
- Asmaa Nabil Elboraey
- Fixed and Removable Prosthodontics Department, National Research Centre, 33 El Buhouth Street, Dokki, P.O.12622 Cairo, Egypt
| | - Hanan Hassan Abo-Almaged
- Refractories, Ceramics and Building Materials Department, National Research Centre, 33 El Buhouth Street, Dokki, P.O.12622, Cairo, Egypt
| | - Ahmed Abd El-Rahman El-Ashmawy
- Medicinal and Pharmaceutical Chemistry Department, Pharmaceutical and Drug Industries Research Division, National Research Centre, 33 EL Bohouth st. (former EL Tahrir st.), Dokki, Giza, Egypt, P.O.12622, Affiliation ID: 10014618
| | - Aya Rashad Abdou
- Medicinal and Pharmaceutical Chemistry Department, Pharmaceutical and Drug Industries Research Division, National Research Centre, 33 EL Bohouth st. (former EL Tahrir st.), Dokki, Giza, Egypt, P.O.12622, Affiliation ID: 10014618
| | - Amani Ramadan Moussa
- Fixed and Removable Prosthodontics Department, National Research Centre, 33 El Buhouth Street, Dokki, P.O.12622 Cairo, Egypt
| | - Laila Hassanian Emara
- Medicinal and Pharmaceutical Chemistry Department, Pharmaceutical and Drug Industries Research Division, National Research Centre, 33 EL Bohouth st. (former EL Tahrir st.), Dokki, Giza, Egypt, P.O.12622, Affiliation ID: 10014618
| | - Hossam Mohammed El-Masry
- Chemistry of Natural Microbial Products Department, National Research Centre,33 El Buhouth Street, Dokki, P.O.12622, Cairo, Egypt
| | - Gehan El-Tabie El Bassyouni
- Refractories, Ceramics and Building Materials Department, National Research Centre, 33 El Buhouth Street, Dokki, P.O.12622, Cairo, Egypt
| | - Magda Ismail Ramzy
- Fixed and Removable Prosthodontics Department, National Research Centre, 33 El Buhouth Street, Dokki, P.O.12622 Cairo, Egypt
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Lainović T, Margueritat J, Martinet Q, Dagany X, Blažić L, Pantelić D, Rabasović MD, Krmpot AJ, Dehoux T. Micromechanical imaging of dentin with Brillouin microscopy. Acta Biomater 2020; 105:214-222. [PMID: 31988041 DOI: 10.1016/j.actbio.2020.01.035] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2019] [Revised: 01/20/2020] [Accepted: 01/21/2020] [Indexed: 01/10/2023]
Abstract
The structure of teeth can be altered by diet, age or diseases such as caries and sclerosis. It is very important to characterize their mechanical properties to predict and understand tooth decay, design restorative dental procedures, and investigate their tribological behavior. However, existing imaging techniques are not well suited to investigating the micromechanics of teeth, in particular at tissue interfaces. Here, we describe a microscope based on Brillouin light scattering (BLS) developed to probe the spectrum of the light scattered from tooth tissues, from which the mechanical properties (sound velocity, viscosity) can be inferred with a priori knowledge of the refractive index. BLS is an inelastic process that uses the scattering of light by acoustic waves in the GHz range. Our microscope thus reveals the mechanical properties at the micrometer scale without contact with the sample. BLS signals show significant differences between sound tissues and pathological lesions, and can be used to precisely delineate carious dentin. We also show maps of the sagittal and transversal planes of sound tubular dentin that reveal its anisotropic microstructure at 1 µm resolution. Our observations indicate that the collagen-based matrix of dentine is the main load-bearing structure, which can be considered as a fiber-reinforced composite. In the vicinity of polymeric tooth-filling materials, we observed the infiltration of the adhesive complex into the opened tubules of sound dentine. The ability to probe the quality of this interfacial layer could lead to innovative designs of biomaterials used for dental restorations in contemporary adhesive dentistry, with possible direct repercussions on decision-making during clinical work. STATEMENT OF SIGNIFICANCE: Mechanical properties of teeth can be altered by diet, age or diseases. Yet existing imaging modalities cannot reveal the micromechanics of the tooth. Here we developed a new type of microscope that uses the scattering of a laser light by naturally-occurring acoustic waves to probe mechanical changes in tooth tissues at a sub-micrometer scale without contact to the sample. We observe significant mechanical differences between healthy tissues and pathological lesions. The contrast in mechanical properties also reveals the microstructure of the polymer-dentin interfaces. We believe that this new development of laser spectroscopy is very important because it should lead to innovative designs of biomaterials used for dental restoration, and allow delineating precisely destructed dentin for minimally-invasive strategies.
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Demirkan I, Unlu MB, Bilen B. Determining sodium diffusion through acoustic impedance measurements using 80 MHz Scanning Acoustic Microscopy: Agarose phantom verification. ULTRASONICS 2019; 94:10-19. [PMID: 30606650 DOI: 10.1016/j.ultras.2018.12.013] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/23/2018] [Revised: 12/22/2018] [Accepted: 12/22/2018] [Indexed: 06/09/2023]
Abstract
The purpose of this study is to explore the feasibility of time-dependent acoustic impedance measurement by Scanning Acoustic Microscopy (SAM) for analyzing the sodium diffusion. The purpose is motivated by the fact that sodium monitoring is challenging and still in the area of exploratory analysis despite its biological importance. To our knowledge, this is the first study in which sodium diffusion has been investigated by time-dependent acoustic impedance measurements provided by SAM. We first tested the idea in an agarose phantom as a proof-of-concept. Accordingly, we designed the agarose phantom which initially contains a well of sodium chloride (NaCl) solution moving radially into the phantom. By using NaCl diffusion in the phantom, we obtained two-dimensional (2D) acoustic impedance (Z) maps over time through SAM operating with 80 MHz ultrasonic transducer having a lateral resolution of 20 μm. A linear correlation between the changes in the concentration profile of the phantom and its acoustic impedance was introduced. Analysis of experimental data proved that spatially changing acoustic impedance could be ascribed to the diffusion process and produced a diffusion coefficient in the order of 10-5 cm2/s which matches well with the literature. Our results showed that SAM could monitor the time-dependent alterations in acoustic impedance resulting from the diffusion of sodium inside the agarose phantom. With this study, SAM shows a promise as a monitoring tool not only to obtain static images but also to perform dynamic investigations of sodium ions with the advantages of providing images in micrometer resolution with a scanning time no longer than 2 min for an image area of 4.8 mm × 4.8 mm.
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Affiliation(s)
- Irem Demirkan
- Bogazici University, Department of Physics, Istanbul 34342, Turkey.
| | - Mehmet Burcin Unlu
- Bogazici University, Department of Physics, Istanbul 34342, Turkey; Global Station for Quantum Medical Science and Engineering, Global Institution for Collaborative Research and Education (GI-CoRE), Hokkaido University, Sapporo 060-8648, Japan; Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA, USA
| | - Bukem Bilen
- Bogazici University, Department of Physics, Istanbul 34342, Turkey
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Alali AY, Al-Khabbaz A, Michael S, Swain MV. Frictional coefficient during flossing of teeth. Dent Mater 2018; 34:1727-1734. [PMID: 30244840 DOI: 10.1016/j.dental.2018.09.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2018] [Accepted: 09/10/2018] [Indexed: 11/18/2022]
Abstract
OBJECTIVE This in-vitro study aimed to develop a technique to measure the frictional forces and determine the frictional coefficient (μ) associated with the rubbing of dental floss against teeth. Incorrect flossing technique and the etiology of grooves at the cementoenamel junction (CEJ) of proximal area of teeth has long been a controversial topic. We hypothesized that the μ between teeth surfaces and dental floss is affected by contact angulation. MATERIALS AND METHODS Tests were conducted using two different types of dental floss (waxed and unwaxed nylon) on different surfaces (enamel, dentine, smooth and rough glass rods) under different moisture conditions (dry and wet). The μ generated by performing C-shape flossing was measured, using the Capstan equation, at constant load (100g) over different flossing contact sliding angulations. In addition, the surface characteristics of intact and used nylon flosses were compared using a scanning electron microscope (SEM). RESULTS The mean μ was highest with a smooth glass rod (0.42±0.11), followed by rough glass rods (0.30±0.07), dry enamel (0.27±0.08), wet enamel (0.23±0.06), then dentine (0.18±0.04). Moreover, higher μ was associated with waxed floss when used against dry enamel, smooth and rough glass rods (P<0.001). At different moisture conditions, waxed floss demonstrated greater μ with dry surfaces (P<0.03). No association was found between μ and dental floss contact angulation. Both floss types showed deterioration after usage; although waxed type exhibited markedly greater deterioration when used on dry surfaces. In conclusion, the magnitude of the μ was found to be influenced by surface roughness, moisture condition, and independent of the contact angulation area during sliding of dental floss. SIGNIFICANCE It is important to consider the potential side effects of frictional forces on both tooth surface and dental floss during clinical application.
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Affiliation(s)
| | | | - S Michael
- Faculty of Dentistry, Kuwait University, Kuwait
| | - M V Swain
- AMME, Sydney University, Sydney, Australia.
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Warkentin M, Freyse C, Specht O, Behrend D, Maletz R, Janda R, Ottl P. Correlation of ultrasound microscopy and Vickers hardness measurements of human dentin and enamel - A pilot study. Dent Mater 2018; 34:1036-1040. [PMID: 29678330 DOI: 10.1016/j.dental.2018.03.020] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2018] [Accepted: 03/24/2018] [Indexed: 10/17/2022]
Abstract
OBJECTIVE To investigate if Vickers microhardness of dentin and enamel correlated with acoustic velocity c(l) or acoustic reflection from the sample's top (amplitude). METHODS Eight transversal sections of a sound human tooth were investigated with scanning acoustic microscopy (SAM) and Vickers microhardness measurements. Longitudinal acoustic velocity c(l), amplitude and microhardness MHV were evaluated and for each c(l) test point corresponding amplitude and MHV were linearly interpolated and graphically analyzed. Spearman rank order correlation (rS) was calculated (p<0.05). RESULTS c(l) was predominantly 6100-7000ms-1 in enamel and 3800-4600ms-1 in dentin and correlated significantly with MHV with 27-420 in enamel and 20-90 in dentin (rs=0,57). Amplitudes significantly correlated with MHV, too, but even better (rs=0,77). SIGNIFICANCE Acoustic velocity and amplitudes were appropriate to detect microhardness differences of dentin and enamel and certain value ranges of both could be assigned to certain MHV ranges. Further research is needed to differentiate more precisely between the different hard tooth tissues.
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Affiliation(s)
- Mareike Warkentin
- Department of Materials Science and Medical Engineering, Friedrich-Barnewitz-Strasse 4, 18119 Rostock, University of Rostock, Germany
| | - Cora Freyse
- Department of Prosthodontics and Materials Science, Strempelstrasse 13, 18057 Rostock, University of Rostock, Germany
| | - Olaf Specht
- Institute of ImplantTechnology and Biomaterials e.V., Rostock, Friedrich-Barnewitz-Strasse 4, 18119 Rostock, Germany
| | - Detlef Behrend
- Department of Materials Science and Medical Engineering, Friedrich-Barnewitz-Strasse 4, 18119 Rostock, University of Rostock, Germany
| | - Reinhard Maletz
- Department of Materials Science and Medical Engineering, Friedrich-Barnewitz-Strasse 4, 18119 Rostock, University of Rostock, Germany
| | - Ralf Janda
- Dept. of Operative and Preventive Dentistry and Endodontics, Centre of Dentistry, Medical Faculty, Heinrich-Heine-University, Moorenstraße 5, Geb. 18.13, D-40225 Düsseldorf, Germany.
| | - Peter Ottl
- Department of Prosthodontics and Materials Science, Strempelstrasse 13, 18057 Rostock, University of Rostock, Germany
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Zingler S, Sommer A, Sen S, Saure D, Langer J, Guillon O, Lux CJ. Efficiency of powered systems for interproximal enamel reduction (IER) and enamel roughness before and after polishing—an in vitro study. Clin Oral Investig 2015; 20:933-42. [PMID: 26419674 DOI: 10.1007/s00784-015-1585-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2014] [Accepted: 08/30/2015] [Indexed: 11/30/2022]
Affiliation(s)
- Sebastian Zingler
- Department of Orthodontics and Dentofacial Orthopaedics, University of Heidelberg, Heidelberg, Germany.
| | - Andreas Sommer
- Department of Orthodontics and Dentofacial Orthopaedics, University of Heidelberg, Heidelberg, Germany
| | - Sinan Sen
- Department of Orthodontics and Dentofacial Orthopaedics, University of Heidelberg, Heidelberg, Germany
| | - Daniel Saure
- Institute of Medical Biometry and Informatics, University of Heidelberg, Heidelberg, Germany
| | - Jochen Langer
- Institute of Materials Science, Technische Universität Darmstadt, Darmstadt, Germany
- Heraeus Holding GmbH, Hanau, Germany
| | - Olivier Guillon
- Institute of Materials Science, Technische Universität Darmstadt, Darmstadt, Germany
- Forschungszentrum Jülich GmbH, Institute of Energy and Climate Research, Materials Synthesis and Processing, Jülich, Germany
| | - Christopher J Lux
- Department of Orthodontics and Dentofacial Orthopaedics, University of Heidelberg, Heidelberg, Germany
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Beshtawi IM, Akhtar R, Hillarby MC, O'Donnell C, Zhao X, Brahma A, Carley F, Derby B, Radhakrishnan H. Biomechanical Changes of Collagen Cross-Linking on Human Keratoconic Corneas Using Scanning Acoustic Microscopy. Curr Eye Res 2015; 41:609-15. [PMID: 26126127 DOI: 10.3109/02713683.2015.1042545] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
PURPOSE To assess the biomechanical changes of collagen cross-linking on keratoconic corneas in vitro. METHODS Six keratoconic corneal buttons were included in this study. Each cornea was divided into two halves, where one half was cross-linked and the other half was treated with riboflavin only and served as control. The biomechanical changes of the corneal tissue were measured across the stroma using scanning acoustic microscopy (SAM). RESULTS In the cross-linked corneas, there was a steady decrease in the magnitude of speed of sound from the anterior region through to the posterior regions of the stroma. The speed of sound was found to decrease slightly across the corneal thickness in the control corneas. The increase in speed of sound between the cross-linked and control corneas in the anterior region was by a factor of 1.039×. CONCLUSION A higher speed of sound was detected in cross-linked keratoconic corneal tissue when compared with their controls, using SAM. This in vitro model can be used to compare to the cross-linking results obtained in vivo, as well as comparing the results obtained with different protocols.
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Affiliation(s)
- Ithar M Beshtawi
- a Optometry Department, Faculty of Medicine and Health Sciences , An-Najah National University , Nablus , State of Palestine
| | - Riaz Akhtar
- b Centre for Materials and Structures, School of Engineering, University of Liverpool , Liverpool , UK
| | - M Chantal Hillarby
- c Stopford Building, Centre For Tissue Injury and Repair, Institute of Inflammation and Repair, University of Manchester , Manchester , UK
| | - Clare O'Donnell
- d Optegra Eye Sciences, Optegra Manchester Eye Hospital , Manchester , UK
| | - Xuegen Zhao
- e Manchester Materials Science Centre, School of Materials, The University of Manchester , Manchester , UK
| | - Arun Brahma
- f Manchester Royal Eye Hospital, Central Manchester University Hospitals NHS Foundation Trust, Manchester Academic Health Science Centre , Manchester , UK and
| | - Fiona Carley
- f Manchester Royal Eye Hospital, Central Manchester University Hospitals NHS Foundation Trust, Manchester Academic Health Science Centre , Manchester , UK and
| | - Brian Derby
- e Manchester Materials Science Centre, School of Materials, The University of Manchester , Manchester , UK
| | - Hema Radhakrishnan
- g Faculty of Life Sciences , The University of Manchester , Manchester , UK
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Effect of gamma irradiation on the wear behaviour of human tooth enamel. Sci Rep 2015; 5:11568. [PMID: 26099692 PMCID: PMC4477323 DOI: 10.1038/srep11568] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2015] [Accepted: 05/28/2015] [Indexed: 02/05/2023] Open
Abstract
Radiotherapy is a frequently used treatment for oral cancer. Extensive research has been conducted to detect the mechanical properties of dental hard tissues after irradiation at the macroscale. However, little is known about the influence of irradiation on the tribological properties of enamel at the micro- or nanoscale. Therefore, this study aimed to investigate the effect of gamma irradiation on the wear behaviour of human tooth enamel in relation to prism orientation. Nanoscratch tests, surface profilometer and scanning electron microscope (SEM) analysis were used to evaluate the friction behaviour of enamel slabs before and after treatment with identical irradiation procedures. X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) were performed to analyse the changes in crystallography and chemical composition induced by irradiation. Surface microhardness (SMH) alteration was also evaluated. The results showed that irradiation resulted in different scratch morphologies, friction coefficients and remnant depth and width at different loads. An inferior nanoscratch resistance was observed independent of prism orientation. Moreover, the variation of wear behaviours was closely related to changes in the crystallography, chemical composition and SMH of the enamel. Together, these measures indicated that irradiation had a direct deleterious effect on the wear behaviour of human tooth enamel.
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Grimal Q, Rohrbach D, Grondin J, Barkmann R, Glüer CC, Raum K, Laugier P. Modeling of femoral neck cortical bone for the numerical simulation of ultrasound propagation. ULTRASOUND IN MEDICINE & BIOLOGY 2014; 40:1015-1026. [PMID: 24486239 DOI: 10.1016/j.ultrasmedbio.2013.11.010] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2013] [Revised: 10/30/2013] [Accepted: 11/06/2013] [Indexed: 06/03/2023]
Abstract
Quantitative ultrasound assessment of the cortical compartment of the femur neck (FN) is investigated with the goal of achieving enhanced fracture risk prediction. Measurements at the FN are influenced by bone size, shape and material properties. The work described here was aimed at determining which FN material properties have a significant impact on ultrasound propagation around 0.5 MHz and assessing the relevancy of different models. A methodology for the modeling of ultrasound propagation in the FN, with a focus on the modeling of bone elastic properties based on scanning acoustic microscopy data, is introduced. It is found that the first-arriving ultrasound signal measured in through-transmission at the FN is not influenced by trabecular bone properties or by the heterogeneities of the cortical bone mineralized matrix. In contrast, the signal is sensitive to variations in cortical porosity, which can, to a certain extent, be accounted for by effective properties calculated with the Mori-Tanaka method.
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Affiliation(s)
- Quentin Grimal
- Sorbonne Universités, UPMC Univ Paris 06, UMR 7623, LIP, F-75006, Paris, France; CNRS, UMR 7623, LIP, F-75006, Paris, France.
| | - Daniel Rohrbach
- Julius Wolff Institute and Berlin-Brandenburg School for Regenerative Therapies, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Julien Grondin
- Sorbonne Universités, UPMC Univ Paris 06, UMR 7623, LIP, F-75006, Paris, France; CNRS, UMR 7623, LIP, F-75006, Paris, France
| | - Reinhard Barkmann
- Sektion Biomedizinische Bildgebung, Klinik für Radiologie und Neuroradiologie, Universitätklinikum Schleswig-Holstein, Campus Kiel, Germany
| | - Claus-C Glüer
- Sektion Biomedizinische Bildgebung, Klinik für Radiologie und Neuroradiologie, Universitätklinikum Schleswig-Holstein, Campus Kiel, Germany
| | - Kay Raum
- Julius Wolff Institute and Berlin-Brandenburg School for Regenerative Therapies, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Pascal Laugier
- Sorbonne Universités, UPMC Univ Paris 06, UMR 7623, LIP, F-75006, Paris, France; CNRS, UMR 7623, LIP, F-75006, Paris, France
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Sun K, Yuan L, Shen Z, Xu Z, Zhu Q, Ni X, Lu J. Scanning laser-line source technique for nondestructive evaluation of cracks in human teeth. APPLIED OPTICS 2014; 53:2366-2374. [PMID: 24787406 DOI: 10.1364/ao.53.002366] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2013] [Accepted: 02/25/2014] [Indexed: 06/03/2023]
Abstract
This paper describes the first application of a remote nondestructive laser ultrasonic (LU) system for clinical diagnosis of cracks in human teeth, to our knowledge. It performs non-contact cracks detection on small-dimension teeth samples. Two extracted teeth with different types of cracks (cracked tooth and craze lines), which have different crack depths, are used as experimental samples. A series of ultrasonic waves were generated by a scanning laser-line source technique and detected with a laser-Doppler vibrometer on the two samples. The B-scan images and peak-to-peak amplitude variation curves of surface acoustic waves were obtained for evaluating the cracks' position and depth. The simulation results calculated by finite element method were combined with the experimental results for accurately measuring the depth of crack. The results demonstrate that this LU system has been successfully applied on crack evaluation of human teeth. And as a remote, nondestructive technique, it has great potential for early in vivo diagnosis of cracked tooth and even the future clinical dental tests.
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Beshtawi IM, Akhtar R, Hillarby MC, O’Donnell C, Zhao X, Brahma A, Carley F, Derby B, Radhakrishnan H. Biomechanical changes after repeated collagen cross-linking on human corneas assessed in vitro using scanning acoustic microscopy. Invest Ophthalmol Vis Sci 2014; 55:1549-54. [PMID: 24508795 PMCID: PMC4120094 DOI: 10.1167/iovs.13-13042] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE To explore the biomechanical changes induced by repeated cross-linking using scanning acoustic microscopy (SAM). METHODS Thirty human corneas were divided into three groups. In group A, five corneas were cross-linked once. In group B, five corneas were cross-linked twice, 24 hours apart. In group C, five corneas were cross-linked three times, 24 hours apart. The contralateral controls in all groups had similar treatment but without UV-A. The speed of sound, which is directly proportional to the square root of the tissue's elastic modulus, was assessed using SAM. RESULTS In group A, the speed of sound of the treated corneas was 1677.38 ± 10.70 ms(-1) anteriorly and 1603.90 ± 9.82 ms(-1) posteriorly, while it was 1595.23 ± 9.66 ms(-1) anteriorly and 1577.13 ± 8.16 ms(-1) posteriorly in the controls. In group B, the speed of sound of the treated corneas was 1746.33 ± 23.37 ms(-1) anteriorly and 1631.60 ± 18.92 ms(-1) posteriorly, while it was 1637.57 ± 22.15 ms(-1) anteriorly and 1612.30 ± 22.23 ms(-1) posteriorly in the controls. In group C, the speed of sound of the treated corneas was 1717.97 ± 18.92 ms(-1) anteriorly and 1616.62 ± 17.58 ms(-1) posteriorly, while it was 1628.69 ± 9.37 ms(-1) anteriorly and 1597.68 ± 11.97 ms(-1) posteriorly in the controls. The speed of sound in the anterior (200 × 200 μm) region between the cross-linked and control corneas in groups A, B, and C was increased by a factor of 1.051 (P = 0.005), 1.066 (P = 0.010), and 1.055 (P = 0.005) respectively. However, there was no significant difference among the cross-linked corneas in all groups (P = 0.067). CONCLUSIONS A significant increase in speed of sound was found in all treated groups compared with the control group; however, the difference among the treated groups is not significant, suggesting no further cross-links are induced when collagen cross-linking treatment is repeated.
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Affiliation(s)
- Ithar M. Beshtawi
- Optometry Department, Faculty of Medicine and Health Sciences, An-Najah National University, Nablus, Palestine
| | - Riaz Akhtar
- Centre for Materials and Structures, School of Engineering, University of Liverpool, Liverpool, United Kingdom
| | - M. Chantal Hillarby
- Centre for Regenerative Medicine, Institute of Inflammation and Repair, The University of Manchester, Manchester, United Kingdom
| | | | - Xuegen Zhao
- Manchester Materials Science Centre, School of Materials, The University of Manchester, Manchester, United Kingdom
| | - Arun Brahma
- Manchester Royal Eye Hospital, Central Manchester University Hospitals NHS Foundation Trust, Manchester Academic Health Science Centre, Manchester
| | - Fiona Carley
- Manchester Royal Eye Hospital, Central Manchester University Hospitals NHS Foundation Trust, Manchester Academic Health Science Centre, Manchester
| | - Brian Derby
- Manchester Materials Science Centre, School of Materials, The University of Manchester, Manchester, United Kingdom
| | - Hema Radhakrishnan
- Faculty of Life Sciences, The University of Manchester, Manchester, United Kingdom
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Sun K, Yuan L, Shen Z, Zhu Q, Lu J, Ni X. Experimental and numerical studies for nondestructive evaluation of human enamel using laser ultrasonic technique. APPLIED OPTICS 2013; 52:6896-6905. [PMID: 24085203 DOI: 10.1364/ao.52.006896] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/21/2013] [Accepted: 08/25/2013] [Indexed: 06/02/2023]
Abstract
In this paper, a nondestructive laser ultrasonic technique is used to generate and detect broadband surface acoustic waves (SAWs) on human teeth with different demineralization treatment. A scanning laser line-source technique is used to generate a series of SAW signals for obtaining the dispersion spectrum through a two-dimensional fast Fourier translation method. The experimental dispersion curves of SAWs are studied for evaluating the elastic properties of the sound tooth and carious tooth. The propagation and dispersion of SAWs in human teeth are also been studied using the finite element method. Results from numerical simulation and experiment are compared and discussed, and the elastic properties of teeth with different conditions are evaluated by combining the simulation and experimental results.
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Beshtawi IM, Akhtar R, Hillarby MC, O'Donnell C, Zhao X, Brahma A, Carley F, Derby B, Radhakrishnan H. Biomechanical properties of human corneas following low- and high-intensity collagen cross-linking determined with scanning acoustic microscopy. Invest Ophthalmol Vis Sci 2013; 54:5273-80. [PMID: 23847309 DOI: 10.1167/iovs.13-12576] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE To assess and compare changes in the biomechanical properties of the cornea following different corneal collagen cross-linking protocols using scanning acoustic microscopy (SAM). METHODS Ten donor human corneal pairs were divided into two groups consisting of five corneal pairs in each group. In group A, five corneas were treated with low-fluence (370 nm, 3 mW/cm(2)) cross-linking (CXL) for 30 minutes. In group B, five corneas were treated with high-fluence (370 nm, 9 mW/cm(2)) CXL for 10 minutes. The contralateral control corneas in both groups had similar treatment but without ultraviolet A. The biomechanical properties of all corneas were tested using SAM. RESULTS In group A, the mean speed of sound in the treated corneas was 1677.38 ± 10.70 ms(-1) anteriorly and 1603.90 ± 9.82 ms(-1) posteriorly, while it was 1595.23 ± 9.66 ms(-1) anteriorly and 1577.13 ± 8.16 ms(-1) posteriorly in the control corneas. In group B, the mean speed of sound of the treated corneas was 1665.06 ± 9.54 ms(-1) anteriorly and 1589.89 ± 9.73 ms(-1) posteriorly, while it was 1583.55 ± 8.22 ms(-1) anteriorly and 1565.46 ± 8.13 ms(-1) posteriorly in the untreated control corneas. The increase in stiffness between the cross-linked and control corneas in both groups was by a factor of 1.051×. CONCLUSIONS SAM successfully detected changes in the corneal stiffness after application of collagen cross-linking. A higher speed-of-sound value was found in the treated corneas when compared with the controls. No significant difference was found in corneal stiffness between the corneas cross-linked with low- and high-intensity protocols.
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Biomechanical properties of corneal tissue after ultraviolet-A–riboflavin crosslinking. J Cataract Refract Surg 2013; 39:451-62. [DOI: 10.1016/j.jcrs.2013.01.026] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2012] [Revised: 10/22/2012] [Accepted: 11/09/2012] [Indexed: 11/23/2022]
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18
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Beshtawi IM, Akhtar R, Hillarby MC, O'Donnell C, Zhao X, Brahma A, Carley F, Derby B, Radhakrishnan H. Scanning acoustic microscopy for mapping the microelastic properties of human corneal tissue. Curr Eye Res 2013; 38:437-44. [PMID: 23402595 DOI: 10.3109/02713683.2012.753094] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
PURPOSE To assess the feasibility of applying scanning acoustic microscopy (SAM) on UV cross-linked corneal tissue for mapping and analyzing its biomechanical properties. MATERIALS AND METHODS Five corneal pairs (10 corneas) were used. In each pair, one cornea was cross-linked (epithelium removed, riboflavin application for 45 min and UVA irradiation for 30 min) and the contralateral control cornea was epithelial debrided and treated only with riboflavin for 45 min. Histological sections were prepared and their mechanical properties were examined using SAM. A line profile technique and 2D analysis was used to analyze the mechanical properties of the corneas. Then the corneal paraformaldehyde and unfixed sections were examined histologically using hematoxylin and eosin (H&E) staining. RESULTS In the frozen fresh corneal tissue, the speed of sound of the treated corneas was 1672.5 ± 36.9 ms(-1), while it was 1584.2 ± 25.9 ms(-1) in the untreated corneas. In the paraformaldehyde fixed corneal tissue, the speed of sound of the treated corneas was 1863.0 ± 12.7 ms(-1), while it was 1739.5 ± 30.4 ms(-1) in the untreated corneas. The images obtained from the SAM technique corresponded well with the histological images obtained with H&E staining. CONCLUSION SAM is a novel tool for examining corneal tissue with a high spatial resolution, providing both histological and mechanical data.
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Affiliation(s)
- Ithar M Beshtawi
- Carys Bannister Building, Faculty of Life Sciences, The University of Manchester, Manchester, UK
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Lakshmanan S, Koch T, Brand S, Männicke N, Wicke M, Mörlein D, Raum K. Prediction of the intramuscular fat content in loin muscle of pig carcasses by quantitative time-resolved ultrasound. Meat Sci 2012; 90:216-25. [DOI: 10.1016/j.meatsci.2011.07.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2010] [Revised: 07/05/2011] [Accepted: 07/07/2011] [Indexed: 10/18/2022]
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Harput S, Evans T, Bubb N, Freear S. Diagnostic ultrasound tooth imaging using fractional Fourier transform. IEEE TRANSACTIONS ON ULTRASONICS, FERROELECTRICS, AND FREQUENCY CONTROL 2011; 58:2096-2106. [PMID: 21989873 DOI: 10.1109/tuffc.2011.2059] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
An ultrasound contact imaging method is proposed to measure the enamel thickness in the human tooth. A delay-line transducer with a working frequency of 15 MHz is chosen to achieve a minimum resolvable distance of 400 μm in human enamel. To confirm the contact between the tooth and the transducer, a verification technique based on the phase shift upon reflection is used. Because of the high attenuation in human teeth, linear frequency-modulated chirp excitation and pulse compression are exploited to increase the penetration depth and improve the SNR. Preliminary measurements show that the enamel-dentin boundary creates numerous internal reflections, which cause the applied chirp signals to interfere arbitrarily. In this work, the fractional Fourier transform (FrFT) is employed for the first time in dental imaging to separate chirp signals overlapping in both time and frequency domains. The overlapped chirps are compressed using the FrFT and matched filter techniques. Micro-computed tomography is used for validation of the ultrasound measurements for both techniques. For a human molar, the thickness of the enamel layer is measured with an average error of 5.5% after compressing with the FrFT and 13.4% after compressing with the matched filter based on the average speed of sound in human teeth.
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Affiliation(s)
- Sevan Harput
- Ultrasound Group, School of Electronic and Electrical Engineering, University of Leeds, Leeds, UK.
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22
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Dos Santos S, Prevorovsky Z. Imaging of human tooth using ultrasound based chirp-coded nonlinear time reversal acoustics. ULTRASONICS 2011; 51:667-674. [PMID: 21371732 DOI: 10.1016/j.ultras.2011.01.008] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/28/2010] [Revised: 01/21/2011] [Accepted: 01/22/2011] [Indexed: 05/30/2023]
Abstract
Human tooth imaging sonography is investigated experimentally with an acousto-optic noncoupling set-up based on the chirp-coded nonlinear time reversal acoustic concept. The complexity of the tooth internal structure (enamel-dentine interface, cracks between internal tubules) is analyzed by adapting the nonlinear elastic wave spectroscopy (NEWS) with the objective of the tomography of damage. Optimization of excitations using intrinsic symmetries, such as time reversal (TR) invariance, reciprocity, correlation properties are then proposed and implemented experimentally. The proposed medical application of this TR-NEWS approach is implemented on a third molar human tooth and constitutes an alternative of noncoupling echodentography techniques. A 10 MHz bandwidth ultrasonic instrumentation has been developed including a laser vibrometer and a 20 MHz contact piezoelectric transducer. The calibrated chirp-coded TR-NEWS imaging of the tooth is obtained using symmetrized excitations, pre- and post-signal processing, and the highly sensitive 14 bit resolution TR-NEWS instrumentation previously calibrated. Nonlinear signature coming from the symmetry properties is observed experimentally in the tooth using this bi-modal TR-NEWS imaging after and before the focusing induced by the time-compression process. The TR-NEWS polar B-scan of the tooth is described and suggested as a potential application for modern echodentography. It constitutes the basis of the self-consistent harmonic imaging sonography for monitoring cracks propagation in the dentine, responsible of human tooth structural health.
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Affiliation(s)
- Serge Dos Santos
- Centre-Val de Loire Université, Unitè Mixte de Recherche "Imagerie et Cerveau" INSERM U930-CNRS ERL 3106, Universit'e François Rabelais ENI Val de Loire, Rue de la Chocolaterie, BP3410, 41034 Blois Cedex, France.
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Akhtar R, Sherratt MJ, Watson REB, Kundu T, Derby B. Mapping the Micromechanical Properties of Cryo-sectioned Aortic Tissue with Scanning Acoustic Microscopy. ACTA ACUST UNITED AC 2011; 1132E:ukpmcpa27262. [PMID: 19603080 DOI: 10.1557/proc-1132-z03-07] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Although the gross mechanical properties of ageing tissues have been extensively documented, biological tissues are highly heterogeneous and little is known concerning the variation of micro-mechanical properties within tissues. Here, we use Scanning Acoustic Microscopy (SAM) to map the acoustic wave speed (a measure of stiffness) as a function of distance from the outer adventitial layer of cryo-sectioned ferret aorta. With a 400 MHz lens, the images of the aorta samples matched those obtained following chemical fixation and staining of sections which were viewed with fluorescence microscopy. Quantitative analysis was conducted with a frequency scanning or V(f) technique by imaging the tissue from 960 MHz to 1.1 GHz. Undulating acoustic wave speed (stiffness) distributions corresponded with elastic fibre locations in the tissue; there was a decrease in wave speed of around 40 ms(-1) from the adventitia (outer layer) to the intima (innermost).
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Affiliation(s)
- Riaz Akhtar
- Manchester Materials Science Centre, School of Materials, The University of Manchester, Grosvenor Street, Manchester, M1 7HS, United Kingdom
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Preininger B, Checa S, Molnar FL, Fratzl P, Duda GN, Raum K. Spatial-temporal mapping of bone structural and elastic properties in a sheep model following osteotomy. ULTRASOUND IN MEDICINE & BIOLOGY 2011; 37:474-483. [PMID: 21256668 DOI: 10.1016/j.ultrasmedbio.2010.12.007] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2010] [Revised: 12/06/2010] [Accepted: 12/08/2010] [Indexed: 05/30/2023]
Abstract
The course of bone healing in animal models is conventionally monitored by morphologic approaches, which do not allow the determination of the material properties of the tissues involved. Mechanical characterization techniques are either dedicated to the macroscopic evaluation of the entire organ or to the microscopic evaluation of the tissue matrix. The latter provides insight to regionally specific alterations at the tissue level in the course of healing. In this study, quantitative scanning acoustic microscopy was used at 50 MHz to investigate microstructural and elastic alterations of mineralized callus and cortical tissue after transverse osteotomy in sheep tibiae. Analyses were performed after 2, 3, 6 and 9 weeks of consolidation with stabilization by either a rigid or a semi-rigid external fixator. Increased stiffness and decreased porosity were observed in the callus tissue over the course of the healing process, which was dependent on the fixator type. In the adjacent cortical tissue, stiffness decreased during the first 3 weeks. Cortical porosity increased over time but the time-dependence was different between the two fixator types. The changes of stiffness of cortical and callus tissues were measured with respect to the distance to the periosteal cortex-callus boundary. Stiffness of cortex and callus tissue smoothly decreased as a function of the distance from the inner cortical region. The data obtained in this study can help to understand the processes involved in tissue maturation during endogenous bone healing.
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Affiliation(s)
- Bernd Preininger
- Julius Wolff Institute and Center for Musculoskeletal Surgery, Charité-Universitätsmedizin Berlin, Berlin, Germany
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25
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Marangos O, Misra A, Spencer P, Katz JL. Scanning acoustic microscopy investigation of frequency-dependent reflectance of acid- etched human dentin using homotopic measurements. IEEE TRANSACTIONS ON ULTRASONICS, FERROELECTRICS, AND FREQUENCY CONTROL 2011; 58:585-595. [PMID: 21429849 PMCID: PMC3695421 DOI: 10.1109/tuffc.2011.1841] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Composite restorations in modern restorative dentistry rely on the bond formed in the adhesive-infiltrated acid-etched dentin. The physical characteristics of etched dentin are, therefore, of paramount interest. However, characterization of the acid-etched zone in its natural state is fraught with problems stemming from a variety of sources including its narrow size, the presence of water, heterogeneity, and spatial scale dependency. We have developed a novel homotopic (same location) measurement methodology utilizing scanning acoustic microscopy (SAM). Homotopic measurements with SAM overcome the problems encountered by other characterization/imaging methods. These measurements provide us with acoustic reflectance at the same location of both the pre- and post-etched dentin in its natural state. We have applied this methodology for in vitro measurements on dentin samples. Fourier spectra from acid-etched dentin showed amplitude reduction and shifts of the central frequency that were location dependent. Through calibration, the acoustic reflectance of acid-etched dentin was found to have complex and non-monotonic frequency dependence. These data suggest that acid-etching of dentin results in a near-surface graded layer of varying thickness and property gradations. The measurement methodology described in this paper can be applied to systematically characterize mechanical properties of heterogeneous soft layers and interfaces in biological materials.
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Affiliation(s)
- Orestes Marangos
- Civil, Environmental, and Architectural Engineering Department, University of Kansas, Lawrence, KS
| | - Anil Misra
- Civil, Environmental, and Architectural Engineering Department, University of Kansas, Lawrence, KS
| | - Paulette Spencer
- Mechanical Engineering Department, University of Kansas, Lawrence, KS
| | - J. Lawrence Katz
- Bioengineering Research Center (BERC), University of Kansas, Lawrence, KS
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Zhao X, Wilkinson S, Akhtar R, Sherratt MJ, Watson REB, Derby B. Quantifying Micro-mechanical Properties of Soft Biological Tissues with Scanning Acoustic Microscopy. MATERIALS RESEARCH SOCIETY SYMPOSIA PROCEEDINGS. MATERIALS RESEARCH SOCIETY 2011; 1301:mrsf10-1301-oo13-08. [PMID: 22723722 PMCID: PMC3378028 DOI: 10.1557/opl.2011.572] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
In this study we have established a new approach to more accurately map acoustic wave speed (which is a measure of stiffness) within soft biological tissues at micrometer length scales using scanning acoustic microscopy. By using thin (5 μm thick) histological sections of human skin and porcine cartilage, this method exploits the phase information preserved in the interference between acoustic waves reflected from the substrate surface as well as internal reflections from the acoustic lens. A stack of images were taken with the focus point of acoustic lens positioned at or above the substrate surface, and processed pixel by pixel using custom software developed with LABVIEW and IMAQ (National Instruments) to extract phase information. Scanning parameters, such as acoustic wave frequency and gate position were optimized to get reasonable phase and lateral resolution. The contribution from substrate inclination or uneven scanning surface was removed prior to further processing. The wave attenuation was also obtained from these images.
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Affiliation(s)
- Xuegen Zhao
- School of Materials, the University of Manchester, Manchester, M1 7HS, United Kingdom
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Cao Z, Sun X, Yeh CK, Sun Y. Rechargeable infection-responsive antifungal denture materials. J Dent Res 2010; 89:1517-21. [PMID: 20940361 PMCID: PMC3318022 DOI: 10.1177/0022034510379604] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2010] [Revised: 06/10/2010] [Accepted: 06/17/2010] [Indexed: 11/16/2022] Open
Abstract
Candida-associated denture stomatitis (CADS) is a significant clinical concern. We developed rechargeable infection-responsive antifungal denture materials for potentially managing the disease. Polymethacrylic acid (PMAA) was covalently bound onto diurethane dimethacrylate denture resins in the curing step. The PMAA resins bound cationic antifungal drugs such as miconazole and chlorhexidine digluconate (CG) through ionic interactions. The anticandidal activities of the drug-containing PMAA-resin discs were sustained for a prolonged period of time (weeks and months). Drug release was much faster at acidic conditions (pH 5) than at pH 7. Drugs bound to the denture materials could be "washed out" by treatment with EDTA, and the drug-depleted resins could be recharged with the same or a different class of anticandidal drugs. These results suggest clinical potential of the newly developed antifungal denture materials in the management of CADS and other infectious conditions.
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Affiliation(s)
- Z. Cao
- Biomedical Engineering Program, University of South Dakota, 4800 N Career Ave., Sioux Falls, SD 57107, USA
| | - X. Sun
- Biomedical Engineering Program, University of South Dakota, 4800 N Career Ave., Sioux Falls, SD 57107, USA
| | - C.-K. Yeh
- Department of Dental Diagnostic Science, University of Texas Health Science Center at San Antonio, and Geriatric Research, Education and Clinical Center, Audie L. Murphy Division, South Texas Veterans Health Care System, San Antonio, TX 78229–4404, USA
| | - Y. Sun
- Biomedical Engineering Program, University of South Dakota, 4800 N Career Ave., Sioux Falls, SD 57107, USA
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Raucci-Neto W, Chinelatti MA, Palma-Dibb RG. Ablation Rate and Morphology of Superficial and Deep Dentin Irradiated with Different Er:YAG Laser Energy Levels. Photomed Laser Surg 2008; 26:523-9. [PMID: 19099384 DOI: 10.1089/pho.2007.2201] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- Walter Raucci-Neto
- Department of Restorative Dentistry, School of Dentistry of Ribeirão Preto, University of São Paulo, Faculdade de Odontologia de Ribeirão Preto, São Paulo, SP, Brazil
| | - Michelle Alexandra Chinelatti
- Department of Restorative Dentistry, School of Dentistry of Ribeirão Preto, University of São Paulo, Faculdade de Odontologia de Ribeirão Preto, São Paulo, SP, Brazil
| | - Regina Guenka Palma-Dibb
- Department of Restorative Dentistry, School of Dentistry of Ribeirão Preto, University of São Paulo, Faculdade de Odontologia de Ribeirão Preto, São Paulo, SP, Brazil
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Chinelatti MA, Raucci-Neto W, Corona SAM, Palma-Dibb RG. Effect of erbium:yttrium-aluminum-garnet laser energies on superficial and deep dentin microhardness. Lasers Med Sci 2008; 25:317-24. [PMID: 18982403 DOI: 10.1007/s10103-008-0618-3] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2008] [Accepted: 09/22/2008] [Indexed: 11/30/2022]
Abstract
This study evaluated the microhardness of superficial and deep dentin irradiated with different erbium:yttrium-aluminum-garnet (Er:YAG) laser energies. Seventy-two molars were bisected and randomly assigned to two groups (superficial dentin or deep dentin) and into six subgroups (160 mJ, 200 mJ, 260 mJ, 300 mJ, 360 mJ, and control). After irradiation, the cavities were longitudinally bisected. Microhardness was measured at six points (20 microm, 40 microm, 60 microm, 80 microm, 100 microm, and 200 microm) under the cavity floor. Data were submitted to analysis of variance (ANOVA) and Fisher's tests (alpha = 0.05). Superficial dentin presented higher microhardness than deep dentin; energy of 160 mJ resulted in the highest microhardness and 360 mJ the lowest one. Values at all points were different, exhibiting increasing microhardness throughout; superficial dentin microhardness was the highest at 20 microm with 160 mJ energy; for deep dentin, microhardness after irradiation at 160 mJ and 200 mJ was similar to that of the control. The lowest energy increased superficial dentin microhardness at the closest extent under the cavity; deep dentin microhardness was not altered by energies of 160 mJ and 200 mJ.
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Affiliation(s)
- Michelle Alexandra Chinelatti
- Department of Restorative Dentistry, Ribeirão Preto School of Dentistry, University of São Paulo (USP), Ribeirão Preto, 14040-904, São Paulo, Brazil.
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Raum K. Microelastic imaging of bone. IEEE TRANSACTIONS ON ULTRASONICS, FERROELECTRICS, AND FREQUENCY CONTROL 2008; 55:1417-1431. [PMID: 18986931 DOI: 10.1109/tuffc.2008.817] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Several high-frequency ultrasound techniques have been developed during the last decade with the intention of assessing elastic properties of bone at the tissue level. The basic measurement principles can be divided into: 1) measurement of the compressional wave velocity in thin tissue sections; 2) measurement of surface acoustic wave velocities in thick sections; and 3) derivation of the acoustic impedance from the confocal reflection amplitude in thick sections. In this paper, the 3 principles are described with example measurements given in the frequency range from 50 MHz to 1.2 GHz. The measurements were made with 2 microscopes operating in the pulse-echo mode, either with frequencies up to 200 MHz and time-resolved detection or between 100 MHz and 2 GHz and amplitude detection. The methods are compared and their application potentials and limitations are discussed with respect to the hierarchical structure of cortical bone. Mapping of the confocal reflection amplitude has superior capabilities for deriving quantitative elastic and structural parameters in the heterogeneous bone material. Even at low frequencies (50 MHz), the mineralized tissue matrix can be separated from the larger pores (Haversian canals), and the elastic coefficient in the probing direction can be measured in 2 dimensions. Depending on the type of sample surface preparation (flat or cylindrically shaped), local distribution of a single elastic coefficient or the average transverse isotropic stiffness tensor can be derived. With frequencies in the GHz range, the lamellar bone structure can be analyzed. However, at one GHz, the acoustic wavelength is still one order of magnitude larger than the individual mineralized collagen fibrils. Although the thickness of a lamellar unit can easily be assessed from the acoustic image, the derivation of the anisotropic elastic properties of the mineralized collagen fibrils as well as the detailed structure of a lamella can only be accomplished with further model assumptions.
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Affiliation(s)
- K Raum
- Dept. of Orthopedics, Martin Luther Univ. of Halle-Wittenberg, Halle, Germany.
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