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Riben, C., Lewin, S., Kämpe, J., Öhman, C. & Thor, A. (2023). Quantification of Bone Height and Bone Volume Around Dental Implants After Open Maxillary Sinus Elevation Surgery Using CBCT.. International Journal of Oral & Maxillofacial Implants, 38(4), 789-800
Open this publication in new window or tab >>Quantification of Bone Height and Bone Volume Around Dental Implants After Open Maxillary Sinus Elevation Surgery Using CBCT.
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2023 (English)In: International Journal of Oral & Maxillofacial Implants, ISSN 0882-2786, E-ISSN 1942-4434, Vol. 38, no 4, p. 789-800Article in journal (Refereed) Published
Abstract [en]

Purpose: To assess, using CBCT, the volume and height of bone formation after open maxillary sinus elevation without the use of grafts.

Materials and Methods: The study was retrospective and included 24 patients with a total of 67 implants. CBCT examinations were conducted at baseline (0 to 43 days postsurgery) and after an average healing period of 6.2 months (range: 5.1 to 7.8 months). The image analysis included metal artifact reduction, registration, and a standardized protocol for segmenting the anatomical structures of the maxillary sinus, including calculating the 3D volumetric changes after bone formation. Conventional manual 2D measurement of vertical bone formation was executed for comparison. Clinical factors assumed to be relevant for bone formation were obtained from patient medical records.

Results: One implant was lost before prosthetic loading, representing an early implant loss rate of 1.5%. Differences in intra- and interexaminer reproducibility were registered for the conventional 2D method (P < .05). The average vertical bone formation measured with the 2D method was 4.8 mm (4.6 to 5.0 mm), covering 60.2% of the implant height within the sinus. The average volumetric bone formation measured with the developed 3D image-analysis method was 801 mm3 in total and 195 mm3 in a restricted region around each implant. Bone formation was registered in 62% of the volume of the restricted region. A correlation regarding bone formation was found between the two methods (R2 = 0.705). Clinical factors such as age, smoking, general health, and postoperative complications did not correlate with the amount of bone formed.

Conclusion: CBCT image analysis is a promising method for objective 3D evaluation of bone formation after sinus elevation. A correlation was seen between the manually measured bone height (2D) and the bone volume in a restricted region around each implant using the developed method (3D). Reducing visual interpretation minimizes errors related to examiner reliability. Clinical factors did not significantly affect the volumetric bone formation.

Place, publisher, year, edition, pages
Quintessence Publishing, 2023
Keywords
3D, bone volume, CBCT, graftless, sinus elevation
National Category
Dentistry
Identifiers
urn:nbn:se:uu:diva-515131 (URN)10.11607/jomi.10183 (DOI)001142545300018 ()37669523 (PubMedID)
Available from: 2023-10-27 Created: 2023-10-27 Last updated: 2024-03-21Bibliographically approved
Ghandour, S., Christie, I., Öhman, C. & Persson, C. (2023). Quasi-static and dynamic mechanical properties of a low-modulus bone cement for spinal applications. Open Research Europe, 3, Article ID 203.
Open this publication in new window or tab >>Quasi-static and dynamic mechanical properties of a low-modulus bone cement for spinal applications
2023 (English)In: Open Research Europe, E-ISSN 2732-5121, Vol. 3, article id 203Article in journal (Refereed) Published
Abstract [en]

Background:

Polymethylmethacrylate (PMMA) bone cement is extensively used in spinal procedures such as vertebroplasty and kyphoplasty, while its use in percutaneous cement discoplasty (PCD) is not yet widely spread. A main issue for both application sites, vertebra and disc, is the mismatch in stiffness between cement and bone, potentially resulting in adjacent vertebral fractures and adjacent segment disease. Tailoring the cement modulus using additives is hence an interesting strategy. However, there is a lack of data on the tensile and tension-compression fatigue properties of these cements, relevant to the newly researched indication of PCD. 

Method:

A commercial PMMA cement (VS) was modified with 12%vol of linoleic acid (VSLA) and tested for quasi-static tensile properties. Additionally, tension-compression fatigue testing with amplitudes ranging from +/-5MPa to +/-7MPa and +/-9MPa was performed, and a Weibull three-parameter curve fit was used to calculate the fatigue parameters. 

Results:

Quasi-static testing revealed a significant reduction in VSLA’s Young’s Modulus (E=581.1±126.4MPa) compared to the original cement (E=1478.1±202.9MPa). Similarly, the ultimate tensile stress decreased from 36.6±1.5MPa to 11.6±0.8MPa. Thus, VSLA offers improved compatibility with trabecular bone properties. Fatigue testing of VSLA revealed that as the stress amplitude increased the Weibull mean number decreased from 3591 to 272 and 91 cycles, respectively. In contrast, the base VS cement reached run-out at the highest stress amplitude. However, the lowest stress amplitude used exceeds the pressures recorded in the disc in vivo, and VSLA displayed a similar fatigue life range to that of the annulus fibrosis tissue.

Conclusions:

While the relevance of fully reversed tension-compression fatigue testing can be debated for predicting cement performance in certain spinal applications, the results of this study can serve as a benchmark for comparison of low-modulus cements for the spine. Further investigations are necessary to assess the clinical feasibility and effectiveness of these cements.

Place, publisher, year, edition, pages
European Commission, 2023
Keywords
PMMA, bone cement, vertebroplasty, discoplasty, fatigue, tensile properties
National Category
Biomaterials Science
Research subject
Engineering Science with specialization in Biomedical Engineering
Identifiers
urn:nbn:se:uu:diva-516530 (URN)10.12688/openreseurope.16683.2 (DOI)
Funder
EU, Horizon 2020, 812765
Available from: 2023-11-24 Created: 2023-11-24 Last updated: 2024-06-03Bibliographically approved
Wu, D., Joffre, T., Öhman, C., Ferguson, S., Persson, C. & Isaksson, P. (2022). A combined experimental and numerical method to estimate the elastic modulus of single trabeculae. Journal of The Mechanical Behavior of Biomedical Materials, 125, Article ID 104879.
Open this publication in new window or tab >>A combined experimental and numerical method to estimate the elastic modulus of single trabeculae
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2022 (English)In: Journal of The Mechanical Behavior of Biomedical Materials, ISSN 1751-6161, E-ISSN 1878-0180, Vol. 125, article id 104879Article in journal (Refereed) Published
Abstract [en]

The elastic modulus at the single trabecular level is an important parameter for the understanding of the mechanical behavior of trabecular bone. Current methods are commonly limited by the irregular trabecular shape and the accuracy of displacement measurement. The aim of this study was to propose a method to estimate the trabecular modulus overcoming some of these limitations. For high-precision displacement measurements, insitu compression within a synchrotron radiation based X-ray tomograph was used. Trabecular displacements were subsequently estimated by a global digital volume correlation algorithm, followed by high-resolution finite element analyses to account for the irregular geometry. The trabecular elastic moduli were then estimated by comparing the loads from the finite element analyses with those of the experiments. With this strategy, the average elastic modulus was estimated to 3.83 +/- 0.54 GPa for three human trabeculae samples. Though limited by the sample size, the demonstrated method shows a potential to estimate the mechanical properties at the single trabecular level.

Place, publisher, year, edition, pages
ElsevierElsevier, 2022
National Category
Applied Mechanics Condensed Matter Physics
Research subject
Engineering Science with specialization in Materials Science
Identifiers
urn:nbn:se:uu:diva-330457 (URN)10.1016/j.jmbbm.2021.104879 (DOI)000717851400005 ()34736021 (PubMedID)
Funder
Göran Gustafsson Foundation for Research in Natural Sciences and MedicineSwedish Research Council
Available from: 2019-08-12 Created: 2019-08-12 Last updated: 2024-01-15Bibliographically approved
Habicher, J., Varshney, G. K., Waldmann, L., Snitting, D., Allalou, A., Zhang, H., . . . Ledin, J. (2022). Chondroitin/dermatan sulfate glycosyltransferase genes are essential for craniofacial development. PLOS Genetics, 18(2), Article ID e1010067.
Open this publication in new window or tab >>Chondroitin/dermatan sulfate glycosyltransferase genes are essential for craniofacial development
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2022 (English)In: PLOS Genetics, ISSN 1553-7390, E-ISSN 1553-7404, Vol. 18, no 2, article id e1010067Article in journal (Refereed) Published
Abstract [en]

Chondroitin/dermatan sulfate (CS/DS) proteoglycans are indispensable for animal development and homeostasis but the large number of enzymes involved in their biosynthesis have made CS/DS function a challenging problem to study genetically. In our study, we generated loss-of-function alleles in zebrafish genes encoding CS/DS biosynthetic enzymes and characterized the effect on development in single and double mutants. Homozygous mutants in chsy1, csgalnact1a, csgalnat2, chpfa, ust and chst7, respectively, develop to adults. However, csgalnact1a-/- fish develop distinct craniofacial defects while the chsy1-/- skeletal phenotype is milder and the remaining mutants display no gross morphological abnormalities. These results suggest a high redundancy for the CS/DS biosynthetic enzymes and to further reduce CS/DS biosynthesis we combined mutant alleles. The craniofacial phenotype is further enhanced in csgalnact1a-/-;chsy1-/- adults and csgalnact1a-/-;csgalnact2-/- larvae. While csgalnact1a-/-;csgalnact2-/- was the most affected allele combination in our study, CS/DS is still not completely abolished. Transcriptome analysis of chsy1-/-, csgalnact1a-/- and csgalnact1a-/-;csgalnact2-/- larvae revealed that the expression had changed in a similar way in the three mutant lines but no differential expression was found in any of fifty GAG biosynthesis enzymes identified. Thus, zebrafish larvae do not increase transcription of GAG biosynthesis genes as a consequence of decreased CS/DS biosynthesis. The new zebrafish lines develop phenotypes similar to clinical characteristics of several human congenital disorders making the mutants potentially useful to study disease mechanisms and treatment.

Place, publisher, year, edition, pages
Public Library of Science (PLoS), 2022
National Category
Biochemistry and Molecular Biology
Identifiers
urn:nbn:se:uu:diva-473635 (URN)10.1371/journal.pgen.1010067 (DOI)001004241700001 ()35192612 (PubMedID)
Funder
Science for Life Laboratory, SciLifeLab
Note

Correction in: The PLOS Genetics, vol. 18, issue 5, Article no e1010242.

DOI: 10.1371/journal.pgen.1010242

Available from: 2022-04-29 Created: 2022-04-29 Last updated: 2023-10-10Bibliographically approved
Masia, N., Smit, M., Mwamba, I., Fowler, L., Chown, L., Norgren, S., . . . Cornish, L. (2022). Corrosion performance of Ti-Cu alloys targeted for biomedical applications. Suid-Afrikaanse tydskrif vir natuurwetenskap en tegnologie, 40(1), 244-250
Open this publication in new window or tab >>Corrosion performance of Ti-Cu alloys targeted for biomedical applications
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2022 (English)In: Suid-Afrikaanse tydskrif vir natuurwetenskap en tegnologie, ISSN 0254-3486, E-ISSN 2222-4173, Vol. 40, no 1, p. 244-250Article in journal (Refereed) Published
Abstract [en]

The Thermo-Calc™ program and TTTI3 database were used to predict the phases in Ti-Cu with 5, 25, and 40 wt% Cu. Based on the predicted results, experimental work was conducted and the Ti-Cu alloys were produced in a button arc furnace, and characterised in the as-cast and the annealed condition (900°C) followed by water quenching. Microstructures and compositions were determined using an electron probe micro-analyser, and the phases were identified by X-ray diffraction. The corrosion performance was measured by potentiodynamic polarisation in a phosphate buffered saline solution at 37 °C at 7.4 pH while purging with nitrogen gas. The Ti-5Cu and Ti-25Cu alloys comprised (αTi) and Ti2Cu phases, the Ti-40Cu alloy comprised Ti2Cu and TiCu. Although the addition of copper decreased the corrosion performance by down to 75%, the corrosion rates were still within the acceptable range (0.02-0.13 mm/y) for biocompatibility of metallic implants. Annealing at 900 °C did not improve the corrosion performance.

Place, publisher, year, edition, pages
Medpharm Publications, 2022
National Category
Metallurgy and Metallic Materials
Research subject
Engineering Science with specialization in Materials Science
Identifiers
urn:nbn:se:uu:diva-493097 (URN)10.36303/satnt.2021cosaami.45 (DOI)
Funder
The Swedish Foundation for International Cooperation in Research and Higher Education (STINT), SA2017-7127
Available from: 2023-01-11 Created: 2023-01-11 Last updated: 2023-04-25Bibliographically approved
Dyal Ukabhai, K., Curle, U. A., Masia, N. D., Smit, M., Mwamba, I. A., Norgren, S., . . . Cornish, L. A. (2022). Formation of Ti2Cu in Ti-Cu Alloys. JOURNAL OF PHASE EQUILIBRIA AND DIFFUSION, 43(3), 332-344
Open this publication in new window or tab >>Formation of Ti2Cu in Ti-Cu Alloys
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2022 (English)In: JOURNAL OF PHASE EQUILIBRIA AND DIFFUSION, ISSN 1547-7037, Vol. 43, no 3, p. 332-344Article in journal (Refereed) Published
Abstract [en]

One of the major issues with dental implants is failure due to bacterial infection, and additions of copper are known to improve the antimicrobial properties of Ti alloys. There are inconsistencies in the Ti rich area of the Cu-Ti binary phase diagram, hence the need to find out if Ti2Cu or Ti3Cu is formed, and to identify the type of formation of Ti2Cu. Four alloys: 20, 33, 40 and 50 Cu (mass%) were produced by arc melting and studied using SEM, XRD and DSC. The reactions were derived, and the temperatures of the reactions were determined by DSC. The formation of Ti2Cu is congruent, and no Ti3Cu was found.

Place, publisher, year, edition, pages
Springer Nature, 2022
Keywords
binary system, differential scanning calorimetry (DSC), Ti-Cu, Ti2Cu
National Category
Materials Chemistry
Identifiers
urn:nbn:se:uu:diva-485025 (URN)10.1007/s11669-022-00964-7 (DOI)000812888400001 ()
Available from: 2022-09-21 Created: 2022-09-21 Last updated: 2022-09-21Bibliographically approved
Waldmann, L., Leyhr, J., Zhang, H., Allalou, A., Öhman, C. & Haitina, T. (2022). The Role of Gdf5 in the Development of the Zebrafish Fin Endoskeleton. Developmental Dynamics, 251(9), 1535-1549
Open this publication in new window or tab >>The Role of Gdf5 in the Development of the Zebrafish Fin Endoskeleton
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2022 (English)In: Developmental Dynamics, ISSN 1058-8388, E-ISSN 1097-0177, Vol. 251, no 9, p. 1535-1549Article in journal (Refereed) Published
Abstract [en]

The development of the vertebrate skeleton requires a complex interaction of multiple factors to facilitate correct shaping and positioning of bones and joints. Growth and differentiation factor 5 (Gdf5), a member of the transforming growth factor-beta family (TGF-beta) is involved in patterning appendicular skeletal elements including joints. Expression of gdf5 in zebrafish has been detected within the first pharyngeal arch jaw joint, fin mesenchyme condensations and segmentation zones in median fins, however little is known about the functional role of Gdf5 outside of Amniota. 

We generated CRISPR/Cas9 knockout of gdf5 in zebrafish and analysed the resulting phenotype at different developmental stages. Homozygous gdf5 mutant zebrafish display truncated median fin endoskeletal elements and loss of posterior radials in the pectoral fins. 

These findings are consistent with phenotypes observed in human and mouse appendicular skeleton in response to Gdf5 knockout, suggesting a broadly conserved role for Gdf5 in Osteichthyes.

Place, publisher, year, edition, pages
John Wiley & SonsWiley, 2022
Keywords
gdf5, fin, joints, zebrafish, appendicular skeleton, CRISPR/Cas9 mutant
National Category
Developmental Biology
Identifiers
urn:nbn:se:uu:diva-430383 (URN)10.1002/dvdy.399 (DOI)000678743100001 ()
Funder
Swedish Research Council, 621-2012-4673Science for Life Laboratory, SciLifeLab
Available from: 2021-01-08 Created: 2021-01-08 Last updated: 2024-05-07Bibliographically approved
Lewin, S., Fleps, I., Åberg, J., Ferguson, S. J., Engqvist, H., Öhman-Mägi, C., . . . Persson, C. (2021). Additively manufactured mesh-type titanium structures for cranial implants: E-PBF vs. L-PBF. Materials & design, 197, Article ID 109207.
Open this publication in new window or tab >>Additively manufactured mesh-type titanium structures for cranial implants: E-PBF vs. L-PBF
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2021 (English)In: Materials & design, ISSN 0264-1275, E-ISSN 1873-4197, Vol. 197, article id 109207Article in journal (Refereed) Published
Abstract [en]

A patient-specific titanium-reinforced calcium phosphate (CaP–Ti) cranial implant has recently shown promising clinical results. Currently, its mesh-type titanium structure is additively manufactured using laser beam powder bed fusion (L-PBF). Nevertheless, an electron-beam (E-PBF) process could potentially be more time efficient. This study aimed to compare the geometrical accuracy and mechanical response of thin titanium structures manufactured by L-PBF (HIPed) and E-PBF (as-printed). Tensile test (ø = 1.2 mm) and implant specimens were manufactured. Measurements by μCT revealed a deviation in cross-sectional area as compared to the designed geometry: 13–35% for E-PBF and below 2% for L-PBF. A superior mechanical strength was obtained for the L-PBF specimens, both in the tensile test and the implant compression tests. The global peak load in the implant test was 457 ± 9 N and 846 ± 40 N for E-PBF and L-PBF, respectively. Numerical simulations demonstrated that geometrical deviation was the main factor in implant performance and enabled quantification of this effect: 34–39% reduction in initial peak force based on geometry, and only 11–16% reduction based on the material input. In summary, the study reveals an uncertainty in accuracy when structures of sizes relevant to mesh-type cranial implants are printed by the E-PBF method.

Place, publisher, year, edition, pages
Elsevier, 2021
Keywords
Additive manufacturing, Electron beam melting, Powder bed fusion, Finite element models, Surface roughness, Cranial implant
National Category
Medical Materials
Research subject
Engineering Science with specialization in Materials Science
Identifiers
urn:nbn:se:uu:diva-409754 (URN)10.1016/j.matdes.2020.109207 (DOI)000596076800002 ()
Funder
EU, Horizon 2020, E19741Vinnova, 2019-00029
Note

De två första författarna delar förstaförfattarskapet

Available from: 2020-04-28 Created: 2020-04-28 Last updated: 2024-01-15Bibliographically approved
Öhman, C., Holub, O., Wu, D., Hall, R. M. & Persson, C. (2021). Density and mechanical properties of vertebral trabecular bone-A review. JOR SPINE, 4(4), Article ID e1176.
Open this publication in new window or tab >>Density and mechanical properties of vertebral trabecular bone-A review
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2021 (English)In: JOR SPINE, ISSN 2572-1143, Vol. 4, no 4, article id e1176Article, review/survey (Refereed) Published
Abstract [en]

Being able to predict the mechanical properties of vertebrae in patients with osteoporosis and other relevant pathologies is essential to prevent fractures and to develop the most favorable fracture treatments. Furthermore, a reliable prediction is important for developing more patient- and pathology-specific biomaterials. A plethora of studies correlating bone density to mechanical properties has been reported; however, the results are variable, due to a variety of factors, including anatomical site and methodological differences. The aim of this study was to provide a comprehensive literature review on density and mechanical properties of human vertebral trabecular bone as well as relationships found between these properties. A literature search was performed to include studies, which investigated mechanical properties and bone density of trabecular bone. Only studies on vertebral trabecular bone tissue, reporting bone density or mechanical properties, were kept. A large variation in reported vertebral trabecular bone densities, mechanical properties, and relationships between the two was found, as exemplified by values varying between 0.09 and 0.35 g/cm(3) for the wet apparent density and from 0.1 to 976 MPa for the elastic modulus. The differences were found to reflect variations in experimental and analytical processes that had been used, including testing protocol and specimen geometry. The variability in the data decreased in studies where bone tissue testing occurred in a standardized manner (eg, the reported differences in average elastic modulus decreased from 400% to 10%). It is important to take this variability into account when analyzing the predictions found in the literature, for example, to calculate fracture risk, and it is recommended to use the models suggested in the present review to reduce data variability.

Place, publisher, year, edition, pages
John Wiley & SonsWiley, 2021
Keywords
bone density, mechanical properties, trabecular bone, vertebrae
National Category
Orthopaedics Endocrinology and Diabetes
Identifiers
urn:nbn:se:uu:diva-470246 (URN)10.1002/jsp2.1176 (DOI)000716092500001 ()35005442 (PubMedID)
Funder
Swedish Research Council, 621-2011-6258EU, FP7, Seventh Framework Programme, FP7-PEOPLE-2010-268134Göran Gustafsson Foundation for Research in Natural Sciences and Medicine, FOA13H-141Vinnova, 2010-02073
Available from: 2022-03-29 Created: 2022-03-29 Last updated: 2024-01-15Bibliographically approved
Robo, C., Wenner, D., Ubhayasekera, S. J., Hilborn, J., Öhman-Mägi, C. & Persson, C. (2021). Functional properties of low-modulus PMMA bone cements containing linoleic acid. Journal of Functional Biomaterials, 12(1), Article ID 5.
Open this publication in new window or tab >>Functional properties of low-modulus PMMA bone cements containing linoleic acid
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2021 (English)In: Journal of Functional Biomaterials, E-ISSN 2079-4983, Vol. 12, no 1, article id 5Article in journal (Refereed) Published
Abstract [en]

Acrylic bone cements modified with linoleic acid are a promising low-modulus alternative to traditional high-modulus bone cements. However, several key properties remain unexplored, including the effect of autoclave sterilization and the potential use of low-modulus cements in other applications than vertebral augmentation. In this work, we evaluate the effect of sterilization on the structure and stability of linoleic acid, as well as in the handling properties, glass transition temperature, mechanical properties, and screw augmentation potential of low-modulus cement containing the fatty acid. Neither 1H NMR nor SFC-MS/MS analysis showed any detectable differences in autoclaved linoleic acid compared to fresh one. The peak polymerization temperature of the low-modulus cement was much lower (28–30 °C) than that of the high-modulus cement (67 °C), whereas the setting time remained comparable (20–25 min). The Tg of the low-modulus cement was lower (75–78 °C) than that of the high-stiffness cement (103 °C). It was shown that sterilization of linoleic acid by autoclaving did not significantly affect the functional properties of low-modulus PMMA bone cement, making the component suitable for sterile production. Ultimately, the low-modulus cement exhibited handling and mechanical properties that more closely match those of osteoporotic vertebral bone with a screw holding capacity of under 2000 N, making it a promising alternative for use in combination with orthopedic hardware in applications where high-stiffness augmentation materials can result in undesired effects.

Place, publisher, year, edition, pages
MDPI, 2021
Keywords
Acrylic bone cement, low-modulus, mechanical properties, bending, vertebroplasty, screw, pullout, sterilization
National Category
Materials Engineering Medical Materials
Research subject
Engineering Science with specialization in Materials Science
Identifiers
urn:nbn:se:uu:diva-349057 (URN)10.3390/jfb12010005 (DOI)000633108400001 ()33477310 (PubMedID)
Funder
The Royal Swedish Academy of SciencesVinnova, 2017-04670
Note

Authors in thesis list of papers: C. Robo, D. Wenner, M. Nilsson, J. Hilborn, C. Öhman-Mägi, C. Persson

Available from: 2018-04-20 Created: 2018-04-20 Last updated: 2024-05-02Bibliographically approved
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ORCID iD: ORCID iD iconorcid.org/0000-0003-2709-9541

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