| 1. |
- Sotres, Javier, et al.
(författare)
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NanoWear of Salivary Films vs. Substratum Wettability
- 2012
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Ingår i: Journal of Dental Research. - : SAGE Publications. - 0022-0345 .- 1544-0591. ; 91:10, s. 973-978
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Tidskriftsartikel (refereegranskat)abstract
- The pellicle serves as a multifunctional protective layer, providing, e.g., lubrication and remineralization and also acting as a diffusion barrier. In addition, since the formation of the pellicle precedes the adhesion of micro-organisms, it is also important as a conditioning film. We present a novel approach to study the influence of the water wettability of solid surfaces on the strength of adsorbed salivary films. It is based on studying the wear resistance of the films with an atomic force microscope operated in the friction force spectroscopy mode. This methodology provides the strength of the films in terms of the forces needed for breaking and removing them. Our results indicate that these forces are highly dependent on the water wettability of the underlying substrata, decreasing with increasing hydrophobicity. Thus, this study provides valuable information for the design of materials exposed in the oral cavity, i.e., materials that will minimize plaque formation and be easy to clean.
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| 2. |
- Rathnayake, N, et al.
(författare)
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Salivary Matrix Metalloproteinase-8 and -9 and Myeloperoxidase in Relation to Coronary Heart and Periodontal Diseases: A Subgroup Report from the PAROKRANK Study (Periodontitis and Its Relation to Coronary Artery Disease).
- 2015
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Ingår i: PLOS ONE. - : Public Library of Science. - 1932-6203. ; 10:7
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Tidskriftsartikel (refereegranskat)abstract
- Background and Objective: Matrix metalloproteinase (MMP) -8, -9 and myeloperoxidase (MPO) are inflammatory mediators. The potential associations between MMP-8, -9, MPO and their abilities to reflect cardiovascular risk remains to be evaluated in saliva. The objective of this study was to investigate the levels and associations of salivary MMP-8, -9, MPO and tissue inhibitors of metalloproteinase (TIMP)-1 in myocardial infarction (MI) patients and controls with or without periodontitis. Materials and Methods: 200 patients with a first MI admitted to coronary care units in Sweden from May 2010 to December 2011 and 200 controls matched for age, gender, residential area and without previous MI were included. Dental examination and saliva sample collection was performed 6-10 weeks after the MI in patients and at baseline in controls. The biomarkers MMP -8, -9, MPO and TIMP-1 were analyzed by time-resolved immunofluorescence assay (IFMA), Western blot and Enzyme-Linked ImmunoSorbent Assay (ELISA). Results: After compensation for gingivitis, gingival pockets and smoking, the mean salivary levels of MMP-8 (543 vs 440 ng/mL, p = 0.003) and MPO (1899 vs 1637 ng/mL, p = 0.02) were higher in non-MI subjects compared to MI patients. MMP-8, -9 and MPO correlated positively with clinical signs of gingival/periodontal inflammation while TIMP-1 correlated mainly negatively with these signs. The levels of latent and active forms of MMP-8 did not differ between the MI and non-MI groups. Additionally, MMP-8, MPO levels and MMP-8/TIMP-1 ratio were significantly higher in men compared to women with MI. Conclusions: This study shows that salivary levels of the analyzed biomarkers are associated with periodontal status. However, these biomarkers could not differentiate between patients with or without a MI. These findings illustrate the importance to consider the influence of oral conditions when analyzing levels of inflammatory salivary biomarkers.
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| 3. |
- Basak, Togar, et al.
(författare)
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Synthesis and in Vitro Toxicity Assessment of Different Nano-Calcium Phosphate Nanoparticles
- 2022
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Ingår i: Brazilian archives of biology and technology. - : FapUNIFESP (SciELO). - 1516-8913 .- 1678-4324. ; 65
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Tidskriftsartikel (refereegranskat)abstract
- Nanoscale biomaterials are commonly used in a wide range of biomedical applications such as bone graft substitutes, gene delivery systems, and biologically active agents. On the other hand, the cytotoxic potential of these particles hasn't yet been studied comprehensively to understand whether or not they exert any negative impact on the cellular structures. Here, we undertook the synthesis of beta-tricalcium phosphate (beta-TCP) and biphasic tricalcium phosphate (BCP) nanoparticles (NPs) and determine their concentration-dependent toxic effects in human fetal osteoblastic (hFOB 1.19) cell line. Firstly, BCP and beta-TCP were synthesized using a water-based precipitation technique and characterized by X-Ray Diffraction (XRD), Raman Spectroscopy, and Transmission Electron Microscopy (TEM). The cytological effects of beta-TCP and BCP at different concentrations (0-640 ppm) were evaluated by using 3- (4,5-dimethylthiazol-2-yl) -2,5-diphenyltetrazolium bromide (MTT) and lactate dehydrogenase (LDH) assays. The total oxidative status (TOS) parameter was used for investigating oxidative stress potentials of the NPs. In addition, the study assessed the DNA damage product 8-hydroxy-2'-deoxyguanosine (8-Oxo-dG) level in hFOB 1.19 cell cultures. The results indicated that the beta-TCP (above 320 ppm) and BCP (above 80 ppm) NPs exhibited cytotoxicity effects on high concentrations. It was also observed that the oxidative stress increased relatively as the concentrations of NPs increased, aligning with the cytotoxicity results. However, the NPs concentrations of 160 ppm and above increased the level of 8-OH-dG. Consequently, there is a need for more systematic in vivo and in vitro approaches to the toxic effects of both nanoparticles.
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| 4. |
- Colding-Rasmussen, Thomas, et al.
(författare)
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Biomechanical Variability and Usability of a Novel Customizable Fracture Fixation Technique
- 2023
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Ingår i: Bioengineering. - : MDPI AG. - 2306-5354. ; 10:10
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Tidskriftsartikel (refereegranskat)abstract
- A novel in situ customizable osteosynthesis technique, Bonevolent™ AdhFix, demonstrates promising biomechanical properties under the expertise of a single trained operator. This study assesses inter- and intra-surgeon biomechanical variability and usability of the AdhFix osteosynthesis platform. Six surgeons conducted ten osteosyntheses on a synthetic bone fracture model after reviewing an instruction manual and completing one supervised osteosynthesis. Samples underwent 4-point bending tests at a quasi-static loading rate, and the maximum bending moment (BM), bending stiffness (BS), and AdhFix cross-sectional area (CSA: mm²) were evaluated. All constructs exhibited a consistent appearance and were suitable for biomechanical testing. The mean BM was 2.64 ± 0.57 Nm, and the mean BS was 4.35 ± 0.44 Nm/mm. Statistically significant differences were observed among the six surgeons in BM (p < 0.001) and BS (p = 0.004). Throughout ten trials, only one surgeon demonstrated a significant improvement in BM (p < 0.025), and another showed a significant improvement in BS (p < 0.01). A larger CSA corresponded to a statistically significantly higher value for BM (p < 0.001) but not for BS (p = 0.594). In conclusion, this study found consistent biomechanical stability both across and within the surgeons included, suggesting that the AdhFix osteosynthesis platform can be learned and applied with minimal training and, therefore, might be a clinically viable fracture fixation technique. The variability in BM and BS observed is not expected to have a clinical impact, but future clinical studies are warranted.
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| 5. |
- Ferrannini, Giulia, et al.
(författare)
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Long-term prognosis after a first myocardial infarction : eight years follow up of the case-control study PAROKRANK
- 2022
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Ingår i: Scandinavian Cardiovascular Journal. - : Informa UK Limited. - 1401-7431 .- 1651-2006. ; 56:1, s. 337-342
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Tidskriftsartikel (refereegranskat)abstract
- Objective. To explore long-term cardiovascular outcomes and mortality in patients after a first myocardial infarction (MI) compared with matched controls in a contemporary setting. Methods. During 2010-2014 the Swedish study PAROKRANK recruited 805 patients <75 years with a first MI and 805 age-, gender-, and area-matched controls. All study participants were followed until 31 December 2018, through linkage with the National Patient Registry and the Cause of Death Registry. The primary endpoint was the first of a composite of all-cause death, non-fatal MI, non-fatal stroke, and heart failure hospitalization. Event rates in cases and controls were calculated using a Cox regression model, subsequently adjusted for baseline smoking, education level, and marital status. Kaplan-Meier curves were computed and compared by log-rank test. Results. A total of 804 patients and 800 controls (mean age 62 years; women 19%) were followed for a mean of 6.2 (0.2-8.5) years. The total number of primary events was 211. Patients had a higher event rate than controls (log-rank test p < .0001). Adjusted hazard ratio (HR) for the primary outcome was 2.04 (95% CI 1.52-2.73). Mortality did not differ between patients (n = 38; 4.7%) and controls (n = 35; 4.4%). A total of 82.5% patients and 91.3% controls were event-free during the follow up. Conclusions. In this long-term follow up of a contemporary, case-control study, the risk for cardiovascular events was higher in patients with a previous first MI compared with their matched controls, while mortality did not differ. The access to high quality of care and cardiac rehabilitation might partly explain the low rates of adverse outcomes.
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| 6. |
- Pedersen, T. O., et al.
(författare)
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Hyperbaric oxygen stimulates vascularization and bone formation in rat calvarial defects
- 2013
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Ingår i: International Journal of Oral and Maxillofacial Surgery. - : Elsevier BV. - 0901-5027 .- 1399-0020. ; 42:7, s. 907-914
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Tidskriftsartikel (refereegranskat)abstract
- Hyperbaric oxygen (HBO) therapy is used to treat or prevent tissue necrosis in patients undergoing irradiation. Many such patients require reconstructive surgery, but little is known of the effects of HBO on bone vascularization and regeneration. In this study, copolymer poly(L-lactide-co-1,5-dioxepan-2-one) (poly(LLA-co-DXO)) scaffolds were implanted into critical-sized calvarial defects in Wistar rats. The animals were randomly allotted to hyperbaric or normobaric oxygen groups. The treatment group received five sessions weekly for 90 min at increased atmospheric pressure, for up to 4 weeks. Samples were retrieved at weeks 2 and 8, i.e. after a total of 10 and 20 sessions, respectively. The samples were analyzed by real-time reverse transcriptase polymerase chain reaction (RT-PCR) and histology at week 2, and radiographically and histologically at week 8. At week 2, defects treated with HBO exhibited greater numbers of cells positive for the endothelial marker CD31, up-regulated gene expression of osteogenic markers, and down-regulated expression of pro-inflammatory cytokines. At week 8, radiographic examination revealed that calvarial defects subjected to HBO exhibited a higher percentage of radiopacities than normobaric controls, and histological examination disclosed enhanced bone healing. These results confirmed that HBO treatment was effective in stimulating vascularization and bone formation in rat calvarial defects.
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| 7. |
- Ryden, Lars, et al.
(författare)
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Periodontitis Increases the Risk of a First Myocardial Infarction A Report From the PAROKRANK Study
- 2016
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Ingår i: Circulation. - : Lippincott Williams & Wilkins. - 0009-7322 .- 1524-4539. ; 133:6, s. 576-583
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Tidskriftsartikel (refereegranskat)abstract
- Background The relationship between periodontitis (PD) and cardiovascular disease is debated. PD is common in patients with cardiovascular disease. It has been postulated that PD could be causally related to the risk for cardiovascular disease, a hypothesis tested in the Periodontitis and Its Relation to Coronary Artery Disease (PAROKRANK) study. Methods and Results Eight hundred five patients (<75 years of age) with a first myocardial infarction (MI) and 805 age- (mean 628), sex- (male 81%), and area-matched controls without MI underwent standardized dental examination including panoramic x-ray. The periodontal status was defined as healthy (80% remaining bone) or as mild-moderate (from 79% to 66%) or severe PD (<66%). Great efforts were made to collect information on possibly related confounders (approximate to 100 variables). Statistical comparisons included the Student pairwise t test and the McNemar test in 2x2 contingency tables. Contingency tables exceeding 2x2 with ranked alternatives were tested by Wilcoxon signed rank test. Odds ratios (95% confidence intervals) were calculated by conditional logistic regression. PD was more common (43%) in patients than in controls (33%; P<0.001). There was an increased risk for MI among those with PD (odds ratio, 1.49; 95% confidence interval, 1.21-1.83), which remained significant (odds ratio, 1.28; 95% confidence interval, 1.03-1.60) after adjusting for variables that differed between patients and controls (smoking habits, diabetes mellitus, years of education, and marital status). Conclusions In this large case-control study of PD, verified by radiographic bone loss and with a careful consideration of potential confounders, the risk of a first MI was significantly increased in patients with PD even after adjustment for confounding factors. These findings strengthen the possibility of an independent relationship between PD and MI.
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| 8. |
- Powell, Nelson, et al.
(författare)
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Patterns in pharyngeal airflow associated with sleep-disordered breathing
- 2011
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Ingår i: Sleep Medicine. - : Elsevier. - 1389-9457 .- 1878-5506. ; 12:10, s. 966-974
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Tidskriftsartikel (refereegranskat)abstract
- Objective: To establish the feasibility of a noninvasive method to identify pharyngeal airflow characteristics in sleep-disordered breathing.Methods: Four patients with sleep-disordered breathing who underwent surgery or used positive airway pressure devices and four normal healthy controls were studied. Three-dimensional CT imaging and computational fluid dynamics modeling with standard steady-state numerical formulation were used to characterize pharyngeal airflow behavior in normals and pre-and post-treatment in patients. Dynamic flow simulations using an unsteady approach were performed in one patient.Results: The pre-treatment pharyngeal airway below the minimum cross-sectional area obstruction site showed airflow separation. This generated recirculation airflow regions and enhanced turbulence zones where vortices developed. This interaction induced large fluctuations in airflow variables and increased aerodynamic forces acting on the pharyngeal wall. At post-treatment, for the same volumetric flow rate, airflow field instabilities vanished and airflow characteristics improved. Mean maximum airflow velocity during inspiration reduced from 18.3 ± 5.7 m/s pre-treatment to 6.3 ± 4.5 m/s post-treatment (P = 0.002), leading to a reduction in maximum wall shear stress from 4.8 ± 1.7 Pa pre-treatment to 0.9 ± 1.0 Pa post-treatment (P = 0.01). The airway resistance improved from 4.3 ± 1.4 Pa/L/min at pre-treatment to 0.7 ± 0.7 Pa/L/min at post-treatment (P = 0.004). Post-treatment airflow characteristics were not different from normal controls (all P ⩾ 0.39).Conclusions: This study demonstrates that pharyngeal airflow variables may be derived from CT imaging and computational fluid dynamics modeling, resulting in high quality visualizations of airflow characteristics of axial velocity, static pressure, and wall shear stress in sleep-disordered breathing.
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| 9. |
- Abtahi, Jahan, 1965-, et al.
(författare)
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Ibandronate Reduces the Surface Bone Resorption of Mandibular Bone Grafts : A Randomized Trial With Internal Controls
- 2021
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Ingår i: JBMR Plus. - : Wiley. - 2473-4039. ; 5:3
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Tidskriftsartikel (refereegranskat)abstract
- Autologous bone grafts are considered the gold standard for reconstruction of the edentulous alveolar ridges. However, this procedure is associated with unpredictable bone loss caused by physiological bone resorption. Bisphosphonates are antiresorptive drugs that act specifically on osteoclasts, thereby maintaining bone density, volume, and strength. It was hypothesized that the resorption of bone grafts treated with an ibandronate solution would be less advanced than bone grafts treated with saline. Ten patients who underwent bilateral sagittal split osteotomy were included in a randomized double-blind trial with internal controls. Each patient received a bone graft treated with a solution of ibandronate on one side and a graft treated with saline (controls) contralaterally. Radiographs for the measurement of bone volume were obtained at 2 weeks and at 6 months after surgery. The primary endpoint was the difference in the change of bone volume between the control and the ibandronate bone grafts 6 months after surgery. All of the bone grafts healed without complications. One patient was excluded because of reoperation. In eight of the nine patients, the ibandronate bone grafts showed an increase in bone volume compared with baseline, with an average gain of 126 mm(3) (40% more than baseline) with a range of +27 to +218 mm(3). Only one ibandronate-treated graft had a decrease in bone volume (8%). In the controls, an average bone volume loss of -146 mm(3) (58% of baseline) with a range of -29 to -301 mm(3) was seen. In the maxillofacial field, the reconstructions of atrophic alveolar ridges, especially in the esthetical zones, are challenging. These results show that bone grafts locally treated with ibandronate solution increases the remaining bone volume. This might lead to new possibilities for the maxillofacial surgeons in the preservation of bone graft volumes and for dental implant installations.
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| 10. |
- Bergenstråhle, Malin, 1977-, et al.
(författare)
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Force Pulling of Single Cellulose Chains at the Crystalline Cellulose-Liquid Interface : A Molecular Dynamics Study
- 2009
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Ingår i: Langmuir. - : American Chemical Society (ACS). - 0743-7463 .- 1520-5827. ; 25:8, s. 4635-4642
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Tidskriftsartikel (refereegranskat)abstract
- Pulling single cellulose molecules from a crystalline cellulose surface has been modeled by molecular dynamics (MD) simulations of the experimental procedure used in atomic force microscopy (AFM). Specifically, the aim of the study was to investigate cellulose interactions at desorption. Simulations were performed in both water and the organic solvent cyclohexane. Moreover, the effects of initial octamer conformation and orientation with respect to the surface chains were studied. A strong effect from the solvent was observed. In cyclohexane, normal forces of 200-500 pN and energies of 43.5 +/- 6.0 kJ/mol glucose unit were required to pull off the octamer. The normal forces in water were substantially lower, around 58 pN, and the energies were 18.2 +/- 3.6 kJ/mol glucose unit. In addition, the lateral components of the pull-off force were shown to provide information on initial conformation and orientation. Hydrogen bonds between the octamer and surface were analyzed and found to be an important factor in the pull-off behavior. Altogether, it was shown that MD provides detailed information on the desorption processes that may be useful for the interpretation of AFM experiments.
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