| 1. |
- Cecchinato, D., et al.
(författare)
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Bone loss at implants and teeth in the same inter-proximal unit: A radiographic study
- 2018
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Ingår i: Clinical Oral Implants Research. - : Wiley. - 0905-7161 .- 1600-0501. ; 29:4, s. 375-380
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Tidskriftsartikel (refereegranskat)abstract
- ObjectiveThis study was performed to determine whether the distance between an implant and a tooth present in an inter-proximal unit influenced the amount of marginal bone loss that occurred at the two facing (adjacent) surfaces. Materials and methodsOne hundred and eighty patients with a total of 278 inter-proximal units were included. Radiographs of implants that also included adjacent (facing) natural tooth/teeth were digitalized, and various linear measurements were performed using a software program. The marginal bone level and the bone level change that had occurred during a mean of 5.8years were assessed as well as distance between the implant and the adjacent tooth/teeth. ResultsThe mean amount of additional marginal bone loss that took place during the observation period was about 0.4mm at both implants and adjacent tooth surfaces. The horizontal distance between an implant and the facing tooth did not influence the amount of marginal bone loss that had occurred. In most inter-proximal units, more advanced bone loss (>1mm, >2mm) had ensued either at the implant or at the facing tooth surface. Advanced additional bone loss occurred at both the implant and the tooth in only about 3% of the examined subjects. ConclusionBone loss at implants and teeth appears to be a site-specific phenomenon and not dependent on the inter-proximal distance.
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| 2. |
- Toia, Marco, et al.
(författare)
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Clinical Considerations of Adapted Drilling Protocol by Bone Quality Perception
- 2017
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Ingår i: International Journal of Oral & Maxillofacial Implants. - : Quintessence. - 0882-2786 .- 1942-4434. ; 32:6, s. 1288-1295
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: To evaluate insertion torque value ( ITV) and marginal bone loss (MBL) of an implant system after a clinically perceived bone quality-adapted drilling. Materials and Methods: This multicenter retrospective study included patients treated with implants, conventionally loaded, in completely healed sites. Operators customized the osteotomy preparation according to radiographic assessment and their perception of bone quality. Drilling sequence, bone quality, and ITV were recorded at the time of surgery. Radiographs were taken at the time of implant placement and permanent restoration. MBL between implant placement and permanent restoration was calculated. The implant was used as the statistical unit. Demographic and implant characteristics were shown by means of descriptive statistics. Outcome values were compared using analysis of variance (ANOVA) and Kruskal-Wallis tests. Multiple regression models were used to test the effect of independent variables on ITV and MBL. Results: One hundred eighty-eight implants placed in 87 patients were included in the analysis. The mean observation period was 144 +/- 59 days. The mean ITV was 30.8 +/- 15.1 Ncm. ITV differed significantly based on arches (mandible/maxilla) (P = .001), bone quality (P < .001), implant diameter (P = .032), and drilling protocol (P = .019). Median MBL was 0.05 mm (0.00; 0.24). A significant difference was found between the mandible and maxilla (P = .008) and between drilling protocols (P = .011). In particular, significantly higher MBL was found in the undersized drilling protocol. Multiple regression analysis showed that ITV was influenced by bone quality and implant diameter. MBL was influenced by bone quality, implant diameter, ITV, and the interaction between bone quality and ITV. It was estimated that MBL was greater with increased bone density and ITV. Conclusion: Excessive ITV in dense bone can cause negative marginal bone responses. A presurgical radiographic assessment and the perception of bone quality are necessary to select an optimal drilling protocol and to minimize surgical trauma.
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| 3. |
- Cecchinato, Francesca, et al.
(författare)
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In vitro evaluation of human fetal osteoblast response to magnesium loaded mesoporous TiO2 coating.
- 2014
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Ingår i: Journal of Biomedical Materials Research - Part A. - : Wiley. - 1552-4965 .- 1549-3296. ; 102:11, s. 3862-3871
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Tidskriftsartikel (refereegranskat)abstract
- This work aimed to evaluate the in vitro response of Transfected Human Foetal Osteoblast (hFOB) cultured on a magnesium-loaded mesoporous TiO2 coating. The application of mesoporous films on titanium implant surfaces has shown very promising potential to enhance osseointegration. This type of coating has the ability to act as a framework to sustain bioactive agents and different drugs. Magnesium is the element that, after calcium, is the most frequently used to dope titanium implant surfaces, since it is crucial for protein formation, growth factor expression, and aids for bone mineral deposition on implant surfaces. Mesoporous TiO2 films with an average pore-size of 6 nm were produced by the evaporation-induced self-assembly method (EISA) and deposited onto titanium discs. Magnesium loading was performed by soaking the mesoporous TiO2 discs in a magnesium chloride solution. Surface characterization was conducted by SEM, XPS, optical interferometry, and AFM. Magnesium release profile was assessed at different time points using a Magnesium Detection kit. Cell morphology and spreading were observed with SEM. The cytoskeletal organization was stained with TRITC-conjugated Phalloidin and cell viability was evaluated through a mitochondrial colorimetric (MTT) assay. Furthermore, gene expression of bone markers and cell mineralization were analyzed by real time RT-PCR and alizarin-red staining, respectively. The surface chemical analysis by XPS revealed the successful adsorption of magnesium to the mesoporous coating. The AFM measurements revealed the presence of a nanostructured surface roughness. Osteoblasts viability and adhesion as well as the gene expression were unaffected by the addition of magnesium possibly due to its rapid burst release, however, were enhanced by the 3D nanostructure of the TiO2 layer.
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| 4. |
- Cecchinato, Francesca, et al.
(författare)
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Influence of Magnesium Alloy Degradation on Undifferentiated Human Cells
- 2015
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Ingår i: PLOS ONE. - : Public Library of Science. - 1932-6203. ; 10:11
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Tidskriftsartikel (refereegranskat)abstract
- Background Magnesium alloys are of particular interest in medical science since they provide compatible mechanical properties with those of the cortical bone and, depending on the alloying elements, they have the capability to tailor the degradation rate in physiological conditions, providing alternative bioresorbable materials for bone applications. The present study investigates the in vitro short-term response of human undifferentiated cells on three magnesium alloys and high-purity magnesium (Mg). Materials and Methods The degradation parameters of magnesium-silver (Mg2Ag), magnesium-gadolinium (Mg10Gd) and magnesium-rare-earth (Mg4Y3RE) alloys were analysed after 1, 2, and 3 days of incubation in cell culture medium under cell culture condition. Changes in cell viability and cell adhesion were evaluated by culturing human umbilical cord perivascular cells on corroded Mg materials to examine how the degradation influences the cellular development. Results and Conclusions The pH and osmolality of the medium increased with increasing degradation rate and it was found to be most pronounced for Mg4Y3RE alloy. The biological observations showed that HUCPV exhibited a more homogeneous cell growth on Mg alloys compared to high-purity Mg, where they showed a clustered morphology. Moreover, cells exhibited a slightly higher density on Mg2Ag and Mg10Gd in comparison to Mg4Y3RE, due to the lower alkalinisation and osmolality of the incubation medium. However, cells grown on Mg10Gd and Mg4Y3RE generated more developed and healthy cellular structures that allowed them to better adhere to the surface. This can be attributable to a more stable and homogeneous degradation of the outer surface with respect to the incubation time.
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| 5. |
- Cecchinato, Francesca, et al.
(författare)
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Modulation of the nanometer pore size improves magnesium adsorption into mesoporous titania coatings and promotes bone morphogenic protein 4 expression in adhering osteoblasts
- 2016
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Ingår i: Dental Materials. - : Elsevier. - 0109-5641 .- 1879-0097. ; 32:7, s. E148-E158
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Tidskriftsartikel (refereegranskat)abstract
- Objective. Mesoporous (MP) titania films used as implant coatings have recently been considered as release systems for controlled administration of magnesium to enhance initial osteoblast proliferation in vitro. Tuning of the pore size in such titania films is aimed at increasing the osteogenic potential through effects on the total loading capacity and the release profile of magnesium. Methods. In this study, evaporation-induced self-assembly (EISA) was used with different structure-directing agents to form three mesoporous films with average pore sizes of 2 nm (MP1), 6 nm (MP2) and 7 nm (MP3). Mg adsorption and release was monitored using quartz crystal microbalance with dissipation (QCM-D). The film surfaces were characterized with atomic force microscopy (AFM), scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). The effect of different Mg release on osteogenesis was investigated in human fetal osteoblasts (hFOB) using pre-designed osteogenesis arrays and real-time polymerase chain reaction (RT-PCR Results. Results showed a sustained release from all the films investigated, with higher magnesium adsorption into MP1 and MP3 films. No significant differences were observed in the surface nanotopography of the films, either with or without the presence of magnesium. MP3 films (7 nm pore size) had the greatest effect on osteogenesis, up-regulating 15 bone-related genes after 1 week of hFOB growth and significantly promoting bone morphogenic protein (BMP4) expression after 3 weeks of growth Significance. The findings indicate that the increase in pore width on the nano scale significantly enhanced the bioactivity of the mesoporous coating, thus accelerating osteogenesis without creating differences in surface roughness. (C) 2016 The Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved
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| 6. |
- Cecchinato, Francesca
(författare)
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On magnesium-modified titanium coatings and magnesium alloys for oral orthopaedic applications : in vitro investigation
- 2015
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In dentistry and orthopaedic surgery, research to find and developimproved biomaterials is progressing rapidly.Of specific interest is to accelerate bone formation around theimplant surface, which could improve the reliability of the implanteven in patients with compromised situations. Although the surfacemodification of the implant has been proven to certain extent topromote osseointegration, the lack of bone in the patient remains amajor issue and bone augmentation is commonly conducted priorto implant insertion. Synthetic and naturally derived resorbablematerials are commonly used. However, problems such as the lackof optimal mechanical properties or the undesirable materialresorption kinetics still exist and there still remain possibility forimprovement. Clinical approaches for orthopaedic trauma require the use ofnon-resorbable screws, plates and pins made of metallic materialssuch as titanium, cobalt-chrome and stainless steel alloys. Themajor drawback of these materials is the need of implant removalat re-entry. Therefore, the research of bioresorbable materials thatcould withstand the mechanical stresses is an ongoing topic.Based on this clinical reality, the aim of this thesis was toinvestigate the suitability of magnesium (Mg) as a biomaterial forregenerative bone applications. Namely, Mg as a doping materialfor engineered mesoporous titanium implant surfaces (Studies I, IIand III), and as a bioresorbable metal alloy for bone regenerationin bone trauma and bone defects conditions (Study IV).Study I, II, IIIMesoporous titania films produced with evaporation-induced selfassembly(EISA) technique and applied as implant surface coatingsare under investigation as a release system for the controlledadministration of several substances, such as osteoporotic drugs, toenhance early bone anchorage to the implant. Modulating the poresize of such films though the selection of EISA parameters permitsto control the adsorption of such substances into the mesoporousmatrix and their subsequent release into the peri-implant region.Studies I, II and III analysed the effect of Mg incorporation intomesoporous titania coatings towards two cellular models duringearly and later stages of cell activity.Study I characterized the morphology, chemistry, and topographyof mesoporous titania coatings and the effects of Mg-loading onsurface micro- and nano-structures. Mg release was determinedand its effect was evaluated on human foetal osteoblast populations.It was shown that mesoporous films possessed a smoothsurface with pores that faced outward. Mg adsorption did notsubstantially alter the mesoporous surface roughness both atmicro- and nano- levels. Mg was released within 24 hours ofincubation in cell culture conditions, thus its bioactive effect onlyoccurred during initial osteoblasts activity.Study II evaluated the ability of Mg-loaded mesoporous coatings tomodulate multipotent adipose-derived stromal cell differentiationtoward the osteoblast phenotype. The results demonstrated thatMg release had a strong impact on this cellular model, promotingosteoblast marker expression in standard cell culture conditions.Interestingly, Mg significantly promoted the expression of osteopontin,a protein that is essential for early biomaterial-cellosteogenic interaction.In study III, the reagents and EISA parameters in the mesoporousdeposition were varied to generate three mesoporous titaniacoatings with 2-, 6- and 7-nm average pore size, to increase Mgcontent in the interconnected porosity of the films. The effect ofvarious Mg contents released from the three mesoporous structureswas tested on human foetal osteoblasts populations with pre-designedosteogenic PCR arrays and real-time polymerase chainreaction. It was shown that Mg release affected osteogenesis andwas controlled by tuning the pore dimensions of the mesoporousfilms. Increasing pore size by 1 nm (from 6 nm to 7 nm)significantly enhanced the bioactivity of the film without alteringthe surface roughness.Study IVIn orthopaedics Mg alloys has received increasing attention asbioresorbable metals for bone regeneration. However, localizedmaterial degradation is too fast and provokes the premature loss ofmechanical properties, preventing correct cellular development andbone healing in vivo . For this reason, various alloying elements arecombined with high-purity Mg to modulate and optimize degradationbehaviour.Study IV of this thesis investigated the degradation parameters ofMg2Ag, Mg10Gd, and Mg4Y3RE alloys and how the alloysdifferently affect human umbilical cord perivascular cell adhesionand spreading. Mg4Y3RE showed the highest degradation rateand, thereby, the highest trend in increases in pH and osmolality ofthe surrounding fluid. However, both Mg4Y3RE and Mg10Gdallowed cells to better adhere and spread across their degradedsurfaces; in comparison, surface degradation of Mg2Ag was moreaggressive with weak or no visible cellular structures on it.ConclusionsIn summary, the results of the present thesis explored the potentialof Mg for its application in bone tissue regeneration. Titaniumimplant surfaces coated with mesoporous TiO2 thin films andfurther loaded with Mg enhanced bone cell activity and osteoprogenitordevelopment into mature osteoblasts. Thus, mesoporousdeposition followed by Mg loading may be a suitablealternative to existing implant surface treatments.Bioresorbable materials must degrade slowly and uniformly inorder to simulate the tissue healing process. Mg10Gd possessesreduced content of alloying element and a suitable homogenousdegradation pattern in vitro that allows proper adhesion ofundifferentiated cells. Mg10Gd thus represents a biodegradableMg-based material with promising mechanical and biologicalproperties for use in dental and orthopaedic fields.
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| 7. |
- Cecchinato, Francesca, et al.
(författare)
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Osteogenic potential of human adipose-derived stromal cells on 3-dimensional mesoporous TiO2 coating with magnesium impregnation
- 2015
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Ingår i: Materials Science and Engineering C. - : Elsevier BV. - 0928-4931 .- 1873-0191. ; 52, s. 225-234
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this study was to evaluate the osteogenic response of human adipose-derived stromal cells (ADScs) to mesoporous titania (TiO2) coatings produced with evaporation-induced self-assembly method (EISA) and loaded with magnesium. Our emphasis with the magnesium release functionality was to modulate progenitor cell osteogenic differentiation under standard culture conditions. Osteogenic properties of the coatings were assessed for stromal cells by means of scanning electron microscopy (SEM) imaging, colorimetric mitochondrial viability assay (MTT), colorimetric alkaline phosphates activity (ALP) assay and real time RT-polymerase chain reaction (PCR). Using atomic force microscopy (AFM) it was shown that the surface expansion area (S-dr) was strongly enhanced by the presence of magnesium. From MTT results it was shown that ADSc viability was significantly increased on mesoporous surfaces compared to the non-porous one at a longer cell culture time. However, no differences were observed between the magnesium impregnated and non-impregnated surfaces. The alkaline phosphatase activity confirmed that ADSc started to differentiate into the osteogenic phenotype after 2 weeks of culturing. The gene expression profile at 2 weeks of cell growth showed that such coatings were capable to incorporate specific osteogenic markers inside their interconnected nano-pores and, at 3 weeks, ADSc differentiated into osteoblasts. Interestingly, magnesium significantly promoted the osteopontin gene expression, which is an essential gene for the early biomaterial-cell osteogenic interaction. (C) 2015 Elsevier B.V. All rights reserved.
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| 8. |
- Stocchero, Michele, et al.
(författare)
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Influence of different drilling preparation on cortical bone : A biomechanical, histological, and micro-CT study on sheep
- 2018
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Ingår i: Clinical Oral Implants Research. - : John Wiley & Sons. - 0905-7161 .- 1600-0501. ; 29:7, s. 707-715
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Tidskriftsartikel (refereegranskat)abstract
- ObjectiveThe aim of this study was to investigate the extent of cortical bone remodeling between two different drilling protocols by means of histomorphometric, mu-CT, and biomechanical analyses. Material and methodsA total of 48 implants were inserted into the mandible of six sheep following two drilling protocols: Group A (Test, n=24), undersized preparation; Group B (Control, n=24), non-undersized preparation. The animals were euthanatized to obtain 5 and 10weeks of implantation time. Removal torque (RTQ) was measured on 12 implants of each group and the peri-implant bone was mu-CT scanned. Bone volume density (BV/TV) was calculated in pre-determined cylindrical volumes, up to 1.5mm from implant surface. Non-decalcified histology was prepared on the remaining 12 implants from each group, where total bone-to-implant contact (totBIC) and newly-formed BIC (newBIC) was measured. Bone Area Fraction Occupancy (BAFO) was determined in pre-determined areas up to 1.5mm from implant surface. Paired sample t test or Wilcoxon signed-rank test was used to investigate differences between the groups. ResultsGroup A presented significantly increased RTQ value at 5weeks, while no difference was observed at 10weeks. Group B presented increased BV/TV value at 5weeks. Both groups showed comparable values for totBIC at both time-points. However, Group A presented significantly lower newBIC at 5weeks. Higher BAFO was observed in Group B at 5weeks. ConclusionsImplants inserted into undersized sites has an increased biomechanical performance, but provoked major remodeling of the cortical bone during the early healing period compared to non-undersized preparations. After 10weeks, no difference was observed.
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| 9. |
- Westas, Emma, 1982, et al.
(författare)
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Bactericidal effect of photocatalytically-active nanostructured TiO2 surfaces on biofilms of the early oral colonizer, Streptococcus oralis
- 2017
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Ingår i: Journal of Biomedical Materials Research - Part A. - : Wiley. - 1552-4965 .- 1549-3296. ; 105:8, s. 2321-2328
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Tidskriftsartikel (refereegranskat)abstract
- This study evaluated the photocatalytic bactericidal effect of nanostructured anatase-rich titanium dioxide (TiO2) on microbial biofilms. Commercially pure titanium discs were spin-coated with photocatalytic TiO2 nanoparticles (P25). Uncoated discs were used as control (CTRL). Half of the CTRL and half of the P25-coated surfaces were coated with purified saliva (SAL) to give four different groups (CTRL, CTRL + SAL, P25 and P25 + SAL). Streptococcus oralis were allowed to form biofilms on the discs for 18 h and non-adherent cells were rinsed off. Bacterial viability was assessed at time 0 with Live/Dead BacLight staining and epifluorescence microscopy. The remaining discs were divided into a non-UV group and UVA-irradiated (1UV) group (irradiation time, 6 or 24 h). Thereafter, viability was assessed as above. Viability at time 0 was high and no dead cells were seen on any of the surfaces, even after 24 h, in the absence of UVA. However, after 24 h of exposure, the proportion of viable cells was reduced by 40% on the P25 discs compared to 0 and 6 h, and this effect was enhanced with a salivary pellicle. Members of mixed species biofilms differ in their susceptibility to the bactericidal effect of the surfaces tested and further investigations are needed to optimize the conditions.
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