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1.
  • Fröjd, Victoria, 1986, et al. (författare)
  • Importance of Ca(2+) Modifications for Osseointegration of Smooth and Moderately Rough Anodized Titanium Implants - A Removal Torque and Histological Evaluation in Rabbit.
  • 2012
  • Ingår i: Clinical implant dentistry and related research. - : Wiley. - 1708-8208 .- 1523-0899. ; 14:5, s. 737-745
  • Tidskriftsartikel (refereegranskat)abstract
    • Background: Incorporation of Ca(2+) into the titania of anodized titanium surfaces has been found to enhance osseointegration. It provides a stable surface when the ions are incorporated into the oxide layer during the anodizing process. The Ca(2+) may suggestively be prominent sites for mineral induction, attract proteins, and catalyze intracellular cascades. Purpose: The aim of the present study was to evaluate the osseointegration of smooth (S(a) < 0.5µm) and moderately rough (S(a) 1.0-2.0µm) commercially pure titanium implants, with and without Ca(2+) , in order to reflect on the importance of surface chemistry in relation to topography. Materials and Methods: Anodized implants with (OxCa) or without Ca(2+) (Ox), blasted implants (Bl), and blasted anodized implants, with (BlOxCa) or without Ca(2+) (BlOx), were inserted in rabbit femur and tibia. The implant surfaces were characterized using interferometry, scanning electron microscopy, and X-ray photoelectron spectroscopy prior to implant installation. Removal torque (RTQ) measurements were executed on all implants after a healing period of 12 weeks. The implants were, thereafter, removed en bloc with surrounding tissues and prepared for histological evaluations. Results: RTQ measurements of tibial implants revealed significantly higher values for BlOxCa implants (90.7 ± 23.3 Ncm) compared to OxCa (64.6 ± 18.2 Ncm) and BlOx implants (69.7 ± 17.5 Ncm) (p = 0.029). Ca(2+) modification of smooth implants placed in the femur did not reveal any differences. Conclusion: Ca(2+) modification of smooth implants resulted in similar interfacial shear strength as moderately rough implants and Ca(2+) modification of moderately rough implants demonstrated the significantly strongest interfacial shear strength when placed in rabbit tibia. This possibly demonstrated surface chemistry compensating for lesser roughness.
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2.
  • Fröjd, Victoria, 1986, et al. (författare)
  • Increased bone contact to a calcium incorporated oxidized c.p. titanium implant: an in vivo study in rabbit.
  • 2008
  • Ingår i: International Journal of Oral and Maxillofacial Surgery. - : Elsevier BV. - 0901-5027. ; 37:6, s. 561-566
  • Tidskriftsartikel (refereegranskat)abstract
    • The aim of this study was to evaluate the bone response to an oxidized titanium implant (Ox) and a calcium-incorporated oxidized titanium implant (Ca). A blasted titanium implant (Bl) was used as control. The implants were topographically characterized using an optical interferometer and placed: one in each distal femoral metaphysis and two in each proximal tibial metaphysis in rabbits. The rabbits were killed 12 weeks after implant insertion, and the implants and their surrounding tissues were removed en bloc for histomorphometrical evaluations. Topographical evaluation revealed three different surfaces: average height deviation (S(a), microm) values for Ca:Ox:Bl implants were 0.3:0.6:0.9, developed surface area ratios (%) 17:44:31, number of summits per microm(2) 208:136:118, and core fluid retention index values 1.33:1.33:1.38. The mean percentages of bone contact to the implants placed in the tibia (Ca:Ox:Bl) were 47:30:34 and to the implants placed in the femur (Ca:Ox) 32:20. The mean percentages of surrounding bone area for the implants placed in the tibia were 40:47:37 and for the implants placed in the femur 43:46. A significant increase in bone contact was found for smooth (S(a) <0.5 microm) but more densely peaked calcium-incorporated oxidized implants when compared to slightly rougher (S(a)=0.5-1.0 microm) oxidized or blasted implants.
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3.
  • Fröjd, Victoria, et al. (författare)
  • Increased bone contact to a calcium incorporated oxidized commercially pure titanium implant; an in vivo study in rabbit
  • 2008
  • Ingår i: International Journal of Oral and Maxillofacial Surgery. - : Elsevier BV. - 0901-5027 .- 1399-0020. ; 37:6, s. 561-566
  • Tidskriftsartikel (refereegranskat)abstract
    • The aim of this study was to evaluate the bone response to an oxidized titanium implant (Ox) and a calcium-incorporated oxidized titanium implant (Ca). A blasted titanium implant (Bl) was used as control. The implants were topographically characterized using an optical interferometer and placed: one in each distal femoral metaphysis and two in each proximal tibial metaphysis in rabbits. The rabbits were killed 12 weeks after implant insertion, and the implants and their surrounding tissues were removed en bloc for histomorphometrical evaluations. Topographical evaluation revealed three different surfaces: average height deviation (S(a), microm) values for Ca:Ox:Bl implants were 0.3:0.6:0.9, developed surface area ratios (%) 17:44:31, number of summits per microm(2) 208:136:118, and core fluid retention index values 1.33:1.33:1.38. The mean percentages of bone contact to the implants placed in the tibia (Ca:Ox:Bl) were 47:30:34 and to the implants placed in the femur (Ca:Ox) 32:20. The mean percentages of surrounding bone area for the implants placed in the tibia were 40:47:37 and for the implants placed in the femur 43:46. A significant increase in bone contact was found for smooth (S(a) <0.5 microm) but more densely peaked calcium-incorporated oxidized implants when compared to slightly rougher (S(a)=0.5-1.0 microm) oxidized or blasted implants.
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4.
  • Albrektsson, Tomas, 1945, et al. (författare)
  • healing response
  • 2008
  • Ingår i: osseointegration. - : Quintessence Publishing Co, Inc. - 9780867154795 ; , s. 47-50, s. 51-57
  • Bokkapitel (övrigt vetenskapligt/konstnärligt)
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5.
  • Arvidsson, Anna, 1973, et al. (författare)
  • Early interactions between leukocytes and three different potentially bioactive titanium surface modifications
  • 2011
  • Ingår i: Journal of Biomedical Materials Research. Part B - Applied biomaterials. - : Wiley. - 1552-4973 .- 1552-4981. ; 97:2, s. 364-72
  • Tidskriftsartikel (refereegranskat)abstract
    • The aim of the present study was to compare the early interactions between leukocytes and three different surface modifications, suggested as bioactive. Blasted titanium discs were modified by alkali and heat treatment, sodium fluoride treatment, or hydroxyapatite coating. A number of these discs were also immersed in simulated body fluid (SBF) for a week, a treatment which yielded high levels of calcium and phosphate on each surface type. The specimens were exposed for human venous blood for 32 minutes and the respiratory burst response was measured in terms of reactive oxygen species with a luminometer, and coverage of viable cells with a fluorescence microscope after staining steps. The topography, morphology, and chemistry of the surfaces were evaluated with optical interferometry and scanning electron microscopy/energy dispersive X-ray analysis (SEM/EDX). A high respiratory burst response was found for HA coated titanium in comparison with the other surface groups (p < 0.0005). The SBF immersion resulted in an increased respiratory burst response (p < 0.0005) and removed statistically significant differences between the surface groups. Thus, the results in the present study indicate that different titanium surface modifications influence the early inflammatory response differently, and that calcium phosphate compounds increase the inflammatory response.
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6.
  • Arvidsson, Anna, 1973, et al. (författare)
  • Formation of calcium phosphates on titanium implants with four different bioactive surface preparations. An in vitro study
  • 2007
  • Ingår i: Journal of Materials Science-Materials in Medicine. - : Springer Science and Business Media LLC. - 0957-4530 .- 1573-4838. ; 18:10, s. 1945-1954
  • Tidskriftsartikel (refereegranskat)abstract
    • The aim of the present study was to compare the nucleating and growing behaviour on four types of bioactive surfaces by using the simulated body fluid (SBF) model. Titanium discs were blasted and then prepared by alkali and heat treatment, anodic oxidation, fluoridation, or hydroxyapatite coating. The discs were immersed in SBF for 1, 2, 4 and 6 weeks. Calcium phosphates were found on all specimens, as analysed with scanning electron microscopy/energy dispersive X-ray analysis (SEM/EDX). After 1 and 2 weeks of SBF immersion more titanium was accessible with SEM/EDX on the blasted surfaces than the four bioactive surface types, indicating a difference in coverage by calcium phosphates. The Ca/P mean ratio of the surfaces was approximately 1.5 after 1 week, in contrast to the fluoridated specimens which displayed a Ca/P mean ratio of approximately 2. Powder X-ray diffraction (P-XRD) analyses showed the presence of hydroxyapatite on all types of surfaces after 4 and 6 weeks of immersion. The samples immersed for 6 weeks showed a higher degree of crystallinity than the samples immersed for 4 weeks. In conclusion, differences appeared at the early SBF immersion times of 1 and 2 weeks between controls and bioactive surface types, as well as between different bioactive surface types.
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7.
  • Arvidsson, Anna, 1973, et al. (författare)
  • Nucleation and growth of calcium phosphates in the presence of fibrinogen on titanium implants with four potentially bioactive surface preparations. An in vitro study.
  • 2009
  • Ingår i: Journal of Materials Science: Materials in Medicine. - : Springer Science and Business Media LLC. - 0957-4530 .- 1573-4838. ; 20:9, s. 1869-1879
  • Tidskriftsartikel (refereegranskat)abstract
    • Abstract The aim of this study was to compare the nucleating and crystal growth behaviour of calcium phosphates on four types of potentially bioactive surfaces, using the simulated body fluid (SBF) model with added fibrinogen. Blasted titanium discs were modified by alkali and heat treatment, anodic oxidation, fluoride treatment, or hydroxyapatite coating. The discs were immersed in SBF with fibrinogen for periods of 3 days and 1, 2, 3 and 4 weeks. The topography, morphology, and chemistry of the surfaces were evaluated with optical interferometry, scanning electron microscopy/energy dispersive X-ray analysis (SEM/EDX), and x-ray photoelectron spectroscopy (XPS), respectively. All surface modifications showed early calcium phosphate formation after 3 days, and were almost completely covered by calcium phosphates after 2 weeks. After 4 weeks, the Ca/P ratio was approximately 2.0 for all surface groups except the fluoride modified surface, which had a Ca/P ratio of 1.0–1.5. XPS measurements of the nitrogen concentration, which can be interpreted as an indirect measure of the protein content, reached a peak value after 3 days immersion and decreased thereafter. In conclusion, the results in the present study, when compared to earlier SBF studies without proteins, showed that fibrinogen stimulates calcium phosphates formation. Furthermore, no pronounced differences could be detected between blasted controls and the potentially bioactive specimens.
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8.
  • Athab Abduljabbar, Zahra, et al. (författare)
  • Chewing side preference and laterality in patients treated with unilateral posterior implant-supported fixed partial prostheses
  • 2022
  • Ingår i: Journal of Oral Rehabilitation. - : Wiley. - 0305-182X .- 1365-2842. ; 49:11, s. 1080-1086
  • Tidskriftsartikel (refereegranskat)abstract
    • Background: It is not clear to what extent chewing is improved by unilateral oral rehabilitation with implant-supported fixed partial prostheses (ISFPPs). Objectives: This study aimed to investigate whether patients treated with unilateral ISFPPs in the maxilla use their prostheses during mastication to the same extent as they used their contralateral natural teeth. A further aim was to investigate whether there is a correlation between preferred chewing side and laterality. Methods: Chewing side preference was assessed in 15 participants treated with unilateral ISFPPs in the maxilla. The first, second, third, fifth and tenth chewing cycles were assessed, and the test was repeated 10 times. All participants also answered a questionnaire about their chewing side preference. Results: Most of the participants presented bilateral chewing, but two (13%) chewed only on the ISFPP. There was no statistically significant association between the objectively assessed chewing side and dental status (natural teeth or ISFPPs) during any of the recorded chewing cycles (p >.1). There were statistically significant correlations between both the subjectively reported usually preferred chewing side and the subjective chewing side preference during the test and the objectively assessed chewing side for the first three chewing cycles (p <.01). No correlation was found between handedness and the objectively assessed chewing side. Conclusion: In the present study, most participants chewed bilaterally, and chewing was performed both on the ISFPP and on the natural teeth. No correlation was found between the preferred chewing side, objectively or subjectively determined and laterality.
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9.
  • Ballerini, Lucia, et al. (författare)
  • Comparison of histomorphometrical data obtained with two different image analysis methods
  • 2007
  • Ingår i: Journal of materials science. Materials in medicine. - : Springer. - 0957-4530 .- 1573-4838. ; 18:8, s. 1471-1479
  • Tidskriftsartikel (refereegranskat)abstract
    • A common way to determine tissue acceptance of biomaterials is to perform histomorphometrical analysis on histologically stained sections from retrieved samples with surrounding tissue, using various methods. The “time and money consuming” methods and techniques used are often “in house standards”. We address light microscopic investigations of bone tissue reactions on un-decalcified cut and ground sections of threaded implants. In order to screen sections and generate results faster, the aim of this pilot project was to compare results generated with the in-house standard visual image analysis tool (i.e., quantifications and judgements done by the naked eye) with a custom made automatic image analysis program. The histomorphometrical bone area measurements revealed no significant differences between the methods but the results of the bony contacts varied significantly. The raw results were in relative agreement, i.e., the values from the two methods were proportional to each other: low bony contact values in the visual method corresponded to low values with the automatic method. With similar resolution images and further improvements of the automatic method this difference should become insignificant. A great advantage using the new automatic image analysis method is that it is time saving—analysis time can be significantly reduced.
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10.
  • Barkarmo, Sargon, et al. (författare)
  • Biofilm formation on polyetheretherketone and titanium surfaces
  • 2019
  • Ingår i: Clinical and Experimental Dental Research. - : Wiley. - 2057-4347. ; 5:4, s. 427-437
  • Tidskriftsartikel (refereegranskat)abstract
    • Objective: Polyetheretherketone (PEEK) is a polymer used in devices in orthopedic and dental rehabilitation. The aim of this in vitro study was to compare biofilm formation by a range of important oral bacterial species on PEEK, blasted PEEK, commercially pure titanium (cp-Ti), and titanium-6 aluminium-4 vanadium (Ti6Al4V). Material and methods: Coin-shaped samples were manufactured, and the surfaces were characterized using optical interferometry, scanning electron microscopy, energy-dispersive X-ray spectroscopy, and contact angle measurements. Bacterial species of Streptococcus sanguinis, Streptococcus oralis, Enterococcus faecalis, and Streptococcus gordonii were cultured on the four material surfaces for varying amounts of time. Biofilms were quantified following staining with crystal violet. Results: Roughness and contact angle results showed blasted PEEK>PEEK>cp-Ti=Ti6Al4V. There was increased biofilm formation on blasted PEEK by S. sanguinis, S. oralis, and S. gordonii, whereas the bacterial adhesion was similar on PEEK, cp-Ti, and Ti6Al4V. The bacterial growth of E. faecalis was significantly higher on cp-Ti compared with the other three groups. Conclusion: The results, taking into consideration the biofilm formation, suggest that PEEK should perform as well as cp-Ti or TiAl6V4 when used as a dental restorative material. © 2019 The Authors. Clinical and Experimental Dental Research published by John Wiley & Sons Ltd.
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11.
  • Barkarmo, Sargon, et al. (författare)
  • Enhanced bone healing around nanohydroxyapatite-coated polyetheretherketone implants : An experimental study in rabbit bone
  • 2014
  • Ingår i: Journal of biomaterials applications. - : Sage Publications. - 0885-3282 .- 1530-8022. ; 29:5, s. 737-747
  • Tidskriftsartikel (refereegranskat)abstract
    • Objective: To investigate the bone response to threaded polyetheretherketone (PEEK) implants coated with nanohydroxyapatite. Materials and methods: A total of 39 PEEK implants were coated with nanocrystalline hydroxyapatite and 39 uncoated implants were used as controls. The implant surface was characterized by optical interferometry and scanning electron microscope. The implants were inserted in the tibia and femur of 13 rabbits. After 6 weeks of healing, quantitative and qualitative analyses were performed. Results: The test implants showed significantly higher removal torque test values compared with the control group. Histomorphometric evaluation demonstrated higher bone-to-implant contact for the test implants; however, there were no differences in bone area between the groups. Qualitative histological analyses demonstrated inflammatory cellular reactions in close vicinity of both implant surfaces. A two-cell layer of foreign body giant cells was observed irrespective of sample type. Conclusion: Our findings demonstrate that implants with a threaded design render good stability to PEEK in both coated and uncoated implants. Nanohydroxyapatite-coated PEEK implants demonstrated improved bone formation compared with uncoated controls.
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12.
  • Barkarmo, Sargon, et al. (författare)
  • Inflammatory cytokine release from human peripheral blood mononuclear cells exposed to polyetheretherketone and titanium-6 aluminum-4 vanadium in vitro.
  • 2018
  • Ingår i: Journal of biomaterials applications. - : SAGE Publications. - 1530-8022 .- 0885-3282. ; 33:2, s. 245-258
  • Tidskriftsartikel (refereegranskat)abstract
    • Objective To investigate the cytokine expression profiles of blood cells exposed to polyetheretherketone and titanium-6 aluminum-4 vanadium materials in vitro. Materials and methods Coin-shaped samples composed of titanium-6 aluminum-4 vanadium, polyetheretherketone, and blasted polyetheretherketone were manufactured. The surfaces of the coins were characterized using optical interferometry, scanning electron microscopy, and contact angle measurements. Peripheral blood mononuclear cells collected from 10 blood donors were cultured for one, three, and six days in the presence or absence of the coins, and then assayed for cytokine production. Quantification of the peripheral blood mononuclear cells attached to the coins was performed using confocal microscopy after immunofluorescence staining. Results The machined titanium-6 aluminum-4 vanadium coins had a smoother surface topography compared to the machined polyetheretherketone and blasted polyetheretherketone. The highest mean contact angle was noted for the blasted polyetheretherketone, followed by the machined polyetheretherketone and titanium-6 aluminum-4 vanadium. The peripheral blood mononuclear cells produced significantly more proinflammatory cytokines when exposed to the polyetheretherketone surface compared to the titanium-6 aluminum-4 vanadium surface, while the blasted polyetheretherketone induced the highest level of proinflammatory cytokine release from the peripheral blood mononuclear cells. Significantly more cells attached to both polyetheretherketone surfaces, as compared to the titanium-6 aluminum-4 vanadium surface. Conclusion Polyetheretherketone induces a stronger inflammatory response from peripheral blood mononuclear cells than does titanium-6 aluminum-4 vanadium. Surface topography has an impact on cytokine release from peripheral blood mononuclear cells.
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13.
  • Barkarmo, Sargon, et al. (författare)
  • Nano-hydroxyapatite-coated PEEK implants : a pilot study in rabbit bone
  • 2013
  • Ingår i: Journal of Biomedical Materials Research. Part A. - : John Wiley & Sons. - 1549-3296 .- 1552-4965. ; 101A:2, s. 465-471
  • Tidskriftsartikel (refereegranskat)abstract
    • Osseointegration of surface-modified polyetheretherketone (PEEK) implants was studied in vivo. A total of 18 cylinder-shaped PEEK implants were inserted in the femurs of nine New Zealand rabbits; half were coated with nanocrystalline hydroxyapatite (nanoHA) and half were uncoated controls. Healing time was 6 weeks. Samples were retrieved with the implant and surrounding tissue, processed to cut and ground sections, and analyzed histomorphometrically. The implant surfaces were analyzed with optical interferometry, scanning electron microscopy (SEM), atomic force microscopy, and X-ray photoelectron spectroscopy (XPS). NanoHA-coated PEEK surfaces had lower height deviation (Sa) than controls [mean ± SD: 0.41 μm (± 0.14) vs. 0.96 μm (± 0.28)]. SEM images showed the nanoHA crystals as a thin layer on the polymer surface. XPS analysis of the coated implants showed a Ca/P ratio of 1.67. Histomorphometry indicated that the nanoHA-coated implants had more bone-to-implant contact [16% (± 4.7) vs. 13% (± 9.3)] and more bone area [52% (± 9.5) vs. 45% (± 11.9)]. We found no difference between smooth nanoHA-coated cylinder-shaped PEEK implants and uncoated controls. However, higher mean bone-to-implant contact indicated better osseointegration in the coated implants than in the uncoated controls. The large number of lost implants was interpreted as a lack of primary stability due to implant design.
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14.
  • Bougas, Kostas, 1980, et al. (författare)
  • In vitro Evaluation of Calcium Phosphate Precipitation on Possibly Bioactive Titanium Surfaces in the Presence of Laminin.
  • 2011
  • Ingår i: Journal of Oral & Maxillofacial Research. - : Stilus Optimus. - 2029-283X. ; 2:3, s. e3-
  • Tidskriftsartikel (refereegranskat)abstract
    • Objectives: The aim of the present study was to evaluate calcium phosphate precipitation and the amount of precipitated protein on three potentially bioactive surfaces when adding laminin in simulated body fluid.Material and Methods: Blasted titanium discs were prepared by three different techniques claimed to provide bioactivity: alkali and heat treatment (AH), anodic oxidation (AO) or hydroxyapatite coating (HA). A blasted surface incubated in laminin-containing simulated body fuid served as a positive control (B) while a blasted surface incubated in non laminin-containing simulated body fuid served as a negative control (B-). The immersion time was 1 hour, 24 hours, 72 hours and 1 week. Surface topography was investigated by interferometry and morphology by Scanning Electron Microscopy (SEM). Analysis of the precipitated calcium and phosphorous was performed by Energy Dispersive X-ray Spectroscopy (EDX) and the adsorbed laminin was quantified by iodine (125I) labeling.Results: SEM demonstrated that all specimens except for the negative control were totally covered with calcium phosphate (CaP) after 1 week. EDX revealed that B- demonstrated lower sum of Ca and P levels compared to the other groups after 1 week. Iodine labeling demonstrated that laminin precipitated in a similar manner on the possibly bioactive surfaces as on the positive control surface.Conclusions: Our results indicate that laminin precipitates equally on all tested titanium surfaces and may function as a nucleation center thus locally elevating the calcium concentration. Nevertheless further studies are required to clarify the role of laminin in the interaction of biomaterials with the host bone tissue.
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15.
  • Bougas, Kostas, 1980, et al. (författare)
  • Laminin Coating Promotes Calcium Phosphate Precipitation on Titanium Discs in vitro.
  • 2011
  • Ingår i: Journal of Oral & Maxillofacial Research. - : Stilus Optimus. - 2029-283X. ; 2:4, s. e5-
  • Tidskriftsartikel (refereegranskat)abstract
    • Objectives: The objective of this study was to investigate the effect of a laminin coating on calcium phosphate precipitation on three potentially bioactive titanium surfaces in simulated body fluid.Material and Methods: Blasted titanium discs were prepared by alkali and heat treatment (AH), anodic oxidation (AO) or hydroxyapatite coating (HA) and subsequently coated with laminin. A laminin coated blasted surface (B) served as a positive control while a blasted non coated (B-) served as a negative control. Surface morphology was examined by Scanning Electron Microscopy (SEM). The analysis of the precipitated calcium and phosphorous was performed by Energy Dispersive X-ray Spectroscopy (EDX).Results: The thickness of the laminin coating was estimated at 26 Å by ellipsometry. Interferometry revealed that the coating process did not affect any of the tested topographical parameters on µm level when comparing B to B-. After 2 weeks of incubation in SBF, the alkali-heat treated discs displayed the highest calcium phosphate deposition and the B group showed higher levels of calcium phosphate than the B- group.Conclusions: Our results suggest that laminin may have the potential to be used as a coating agent in order to enhance the osseoinductive performance of biomaterial surfaces, with the protein molecules possibly functioning as nucleation centres for apatite formation. Nevertheless, in vivo studies are required in order to clarify the longevity of the coating and its performance in the complex biological environment.
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16.
  • Franco Tabares, Sebastian, et al. (författare)
  • Chemical bonding to novel translucent zirconias: A mechanical and molecular investigation
  • 2019
  • Ingår i: Journal of Adhesive Dentistry. - 1757-9988 .- 1461-5185. ; 21:2, s. 107-116
  • Tidskriftsartikel (refereegranskat)abstract
    • Purpose: To investigate direct bonding of a 10-MDP-based cement to two novel translucent yttria-stabilized tetragonal zirconia polycrystal ceramics (4Y-TZP, 5Y-TZP) and observe the influence of thermocycling on this bonding. Materials and Methods: Powders of presintered and isostatically pressed 5Y-TZP, 4Y-TZP and 3Y-TZP were mixed with a 10-MDP-based cement (Panavia F 2.0), then stored in deionized water for 48 h at 37°C or thermocycled 10,000 times. Raman spectroscopy and Fourier-transform infrared spectroscopy were used to assess the presence of a functional group (PO32-) that could indicate bonding before and after thermocycling. X-ray photoelectron spectroscopy was used to identify the presence of the suspected Zr-O-P bond in the same specimens. A shearbond strength (SBS) test was conducted based on ISO 29022:2013. Results: Marked peaks assigned to the asymmetric vibrations of the PO32- functional group were observed in both zirconias before and after thermocycling. The binding energy corresponding to Zr-O-P interactions (531.5 eV) was masked by the aluminosilicate in the filler of the cement. Shear bond strengths were approximately 20 MPa after water storage and approximately 6 MPa after thermocycling. No differences were found between the control group and the translucent zirconias. Conclusion: Direct bonding of the 10-MDP-based cement to both 4Y-TZP and 5Y-TZP was highly plausible. Both 4YTZP and 5Y-TZP may be promising alternatives to glass-ceramic restorations.
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17.
  • Franco Tabares, Sebastian, et al. (författare)
  • Effect of airborne-particle abrasion and polishing on novel translucent zirconias: Surface morphology, phase transformation and insights into bonding
  • 2021
  • Ingår i: Journal of Prosthodontic Research. - : Japan Prosthodontic Society. - 1883-1958 .- 2212-4632. ; 65:1, s. 97-105
  • Tidskriftsartikel (refereegranskat)abstract
    • Purpose: The purpose this study was to investigate the effect of Kern ' s air-borne particle abrasion protocol (KAPA) and polishing on two translucent zirconias (4Y, 5Y-zirconias) compared to a traditional zirconia (3Y-zirconia). Methods: Two different surface treatments were analysed by X-ray diffraction (XRD) and interferometry 1) KAPA (0.1 MPa, 50 mu m alumina, 10-12 mm distance, 15 sec and 30 sec and cleaning in ultrasound using isopropyl alcohol 99%) and 2) Clinical-delivery polishing paste (Zircon Brite, Dental Ventures, USA). Shear-bond strength tests (SBS's) were performed with a highly polished and virtually flat surface in combination with a 10-MDP based cement and a surface modified by KAPA in combination with zinc phosphate cement. The SBS was expressed in terms of MPa. Results: The mean values for monoclinic content were 13 wt%, 7 wt% and 2 wt% for 3Y-, 4Y- and 5Y-zirconias respectively, no differences were found between 15 and 30 seconds. Polishing did not result in phase transformation to monoclinic phase in any of the zirconias. The rhombohedral phase was identified in all types of zirconias regardless of surface treatment. Shear-bond strength tests showed 5 MPa for polished/10-MDP based cement and 3 MPa for KAPA/Zinc phosphate. Statistically significant differences were found between the two different surface treatments but not between the types of zirconias. Conclusions: KAPA for 15 sec seems to be equal to 30 sec regarding morphology and phase transformation. Sole micro-retention appears not to be fully responsible for the bonding phenomena of 10-MDP and zirconia that underwent KAPA.
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18.
  • Franco Tabares, Sebastian, et al. (författare)
  • Limited Effect of Cement Material on Stress Distribution of a Monolithic Translucent Zirconia Crown: A Three-Dimensional Finite Element Analysis.
  • 2018
  • Ingår i: The International journal of prosthodontics. - : Quintessence Publishing. - 0893-2174 .- 1139-9791. ; 31:1, s. 67-70
  • Tidskriftsartikel (refereegranskat)abstract
    • The literature shows that the performance of densely sintered zirconia single crowns seems to be unaffected by the cement material. The purpose of this study was to evaluate the effects of various cement materials on the stress distribution in a monolithic translucent zirconia crown.A crown-cement-dentin complex was modeled. Six cements were evaluated: zinc phosphate, glass-ionomer, resin-modified glass-ionomer, dual-cure resin, calcium aluminate-based, and a theoretical or conceptual cement with mechanical properties close to those of dentin (ie, monoblock cement).While varying stress concentrations were found within the cements, the stress concentrations in the crown and dentin were consistent irrespective of cement material.Within the limitations of this study, it can be concluded that cement material had a negligible effect on stress distribution in the monolithic zirconia crown.
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19.
  • Franke Stenport, Victoria, 1970, et al. (författare)
  • Enamel matrix derivative and titanium implants.
  • 2003
  • Ingår i: Journal of clinical periodontology. - 0303-6979. ; 30:4, s. 359-63
  • Tidskriftsartikel (refereegranskat)abstract
    • AIM: The aim of present study was to evaluate if an enamel matrix derivative (Emdogain) may enhance bone formation and osseointegration of titanium implants, using a well-documented rabbit model. MATERIAL AND METHODS: Thirty-six threaded commercially pure titanium (cp.ti.) implants were inserted in six New Zealand white rabbits. One implant was placed in each femur and two in each tibia. Prior to implant insertion approximately 0.5 mL of Emdogain (EMD) (test) or the vehicle gel (PGA: propylene glycol alginate) (control) was injected into the surgically prepared implant site. The follow-up time was 6 weeks. Biomechanical evaluations by resonance frequency analysis (RFA) and removal torque measurements (RTQ) were performed. Histomorphometrical quantifications were made on ground sections by measurements of the percentage of bone-to-metal contact, bone area inside the threads as well as outside the threads (mirror image). Bone lengths along the implant surface were also measured and used for shear strength calculations. RESULTS: The results demonstrated no beneficial effects from the EMD treatment on bone formation around titanium implants in any of the tested parameters. Significant differences were demonstrated with removal torque test and shear force calculations for the control implants. No other parameter demonstrated a statistically significant difference. CONCLUSION: The results of the present study may indicate that EMD does not contribute to bone formation around titanium implants. This observation may indicate that the bone formation that occurs after EMD treatment in periodontal defects is the result of functional adaptation. However, further research is required to evaluate the effect of EMD treatment on bone formation.
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20.
  • Franke Stenport, Victoria, et al. (författare)
  • Enamel matrix derivative and titanium implants : An experimental pilot study in the rabbit
  • 2003
  • Ingår i: Journal of Clinical Periodontology. - : Blackwell. - 0303-6979 .- 1600-051X. ; 30:4, s. 359-363
  • Tidskriftsartikel (refereegranskat)abstract
    • Aim: The aim of present study was to evaluate if an enamel matrix derivative (Emdogain®) may enhance bone formation and osseointegration of titanium implants, using a well-documented rabbit model. Material and methods: Thirty-six threaded commercially pure titanium (cp.ti.) implants were inserted in six New Zealand white rabbits. One implant was placed in each femur and two in each tibia. Prior to implant insertion approximately 0.5 mL of Emdogain (EMD) (test) or the vehicle gel (PGA: propylene glycol alginate) (control) was injected into the surgically prepared implant site. The follow-up time was 6 weeks. Biomechanical evaluations by resonance frequency analysis (RFA) and removal torque measurements (RTQ) were performed. Histomorphometrical quantifications were made on ground sections by measurements of the percentage of bone-to-metal contact, bone area inside the threads as well as outside the threads (mirror image). Bone lengths along the implant surface were also measured and used for shear strength calculations. Results: The results demonstrated no beneficial effects from the EMD treatment on bone formation around titanium implants in any of the tested parameters. Significant differences were demonstrated with removal torque test and shear force calculations for the control implants. No other parameter demonstrated a statistically significant difference. Conclusion: The results of the present study may indicate that EMD does not contribute to bone formation around titanium implants. This observation may indicate that the bone formation that occurs after EMD treatment in periodontal defects is the result of functional adaptation. However, further research is required to evaluate the effect of EMD treatment on bone formation.
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21.
  • Franke Stenport, Victoria, 1970, et al. (författare)
  • Evaluations of Bone Tissue Integration to Pure and Alloyed Titanium Implants
  • 2008
  • Ingår i: Clinical Implant Dentistry and Related Research. - : Wiley. - 1523-0899 .- 1708-8208. ; 10:3, s. 191-199
  • Tidskriftsartikel (refereegranskat)abstract
    • Purpose: This study was performed for comparisons of tissue integration to commercially pure (CP) and titanium-6-aluminum-4 vanadium (Ti-6-Al-4V) implants using various existing three-dimensional biomechanical and two-dimensional histomorphometrical techniques, and to monitor the loosening torque during in vivo removal torque (RTQ) test with a novel unit not used before in a pilot study in rabbits. Materials and Methods: The implants were topographically characterized and inserted in femurs and tibiae of five rabbits (in total 40 implants, 20 per group). After 16 weeks, the implant integration was biomechanically evaluated by: (1) resonance frequency test, and (2) peak RTQ test and the graph from the monitoring curve. Biopsies of the implants in situ were processed to undecalcified cut and ground sections followed by light microscopical quantifications. Shear strength calculations were performed. Results: Significantly higher mean value of RTQ (p = .01) and shear strength tests (p = .03) were observed for the CP titanium implants compared to Ti-6-Al-4V implants. The monitoring curve from the RTQ test demonstrated no differences in the shape or form that could provide further information about the differences in the implant-to-bone attachment. Conclusions: The CP titanium implants showed increased RTQ and shear strength values compared to the Ti-6-Al-4V implants. The new tool of monitoring the RTQ curve could not demonstrate differences between the two materials. The exact influence of the implant materials on the surrounding tissues needs to be further investigated.
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22.
  • Franke Stenport, Victoria, 1970, et al. (författare)
  • Failure to induce supracrestal bone growth between and around partially inserted titanium implants using bone morphogenetic protein (BMP): an experimental study in dogs.
  • 2003
  • Ingår i: Clinical oral implants research. - : Blackwell Munksgaard. - 0905-7161 .- 1600-0501. ; 14:2, s. 219-25
  • Tidskriftsartikel (refereegranskat)abstract
    • The effect of bone morphogenetic protein on supracrestal bone growth around partially inserted implants in a dog model is described. The lower premolar teeth (P1, P2, P3 and P4) were extracted on both sides of the mandible in six dogs. At a surgical exposure 12 weeks later, two 10-mm turned titanium implants were partially inserted, approximately 15 mm apart, in the areas of the P1 and P3 in each side of the mandible, allowing five threads to protrude from the bone crest. A titanium mesh was fastened to the coronal aspect of the two fixtures and the space beneath the mesh was filled with bone morphogenetic protein (S300 BMP) in combination with an insoluble bone matrix carrier, or with the carrier alone. The mesh was covered with an ePTFE membrane. Thus, a space for potential bone formation was created between the two implants. The surgical flaps were coronally positioned and secured with vertical mattress sutures. After 16 weeks of healing, biopsy specimens were retrieved and examined histologically. Bone was not formed around the protruding implants or in the created space between the implants in any case. The carrier was incompletely resorbed. We conclude that supracrestal bone growth beyond the crestal limit with or without BMP in such a large space as in this experimental design may not be possible.
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23.
  • Franke Stenport, Victoria, 1970, et al. (författare)
  • FGF-4 and titanium implants: a pilot study in rabbit bone.
  • 2003
  • Ingår i: Clinical oral implants research. - : Wiley. - 0905-7161 .- 1600-0501. ; 14:3, s. 363-8
  • Tidskriftsartikel (refereegranskat)abstract
    • AIM: To evaluate the effect of a local single injection of amino-terminally truncated recombinant human fibroblast growth factor-4 (rhFGF-4s) on titanium implant incorporation in a rabbit bone. MATERIAL AND METHODS: Thirty-six threaded titanium implants were inserted into the femur and tibia of six rabbits. Three weeks prior to implant insertion 10 microg of FGF-4 in an altelocollagen carrier or the carrier alone was injected into the intended implant sites. Biomechanical evaluation by (i) resonance frequency analysis and (ii) peak removal torque measurements was performed after 6 weeks. The implants with surrounding tissue were processed to undecalcified ground sections followed by light-microscopic quantifications of the bone in threaded area and the apical parts of the implants. RESULTS: A general trend, however not statistically significant, with higher mean values obtained in the above-mentioned tests was found. The FGF-4-treated implants revealed a significantly increased bone area in the apical part of the implants compared to the corresponding control implants. CONCLUSION: A local single injection of rhFGF-4 may stimulate bone formation around titanium implants in bone. However, further research is required to confirm these results, understand the mechanisms of FGF, and establish optimal dose and delivery methods.
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24.
  • Franke Stenport, Victoria, 1970 (författare)
  • On growth factors and titanium implant integration in bone
  • 2002
  • Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
    • PurposeThe purpose of the present thesis was to investigate the bone tissue response around titanium implants with one growth factor stimulating hormone and a few different growth factor substances.Material and methodsIn four studies (study I to IV) a rabbit model were used and the growth factors i.e. growth hormone (hGH), enamel matrix derivative (EMD), fibroblast growth factor-4s (FGF-4s) or bone morphogenetic protein-7 (BMP-7) was applied around or inside the titanium implants.In study I, 16 Russian rabbits were used and in study II, III and IV a total number of 22 New Zealand White rabbits were used. The follow-up time was 8 weeks in study I, 6 weeks in study II and III and 4 weeks in study IV. In two studies (study V and VI) a Labrador dog model with partially inserted implants was used. A total number of 10 dogs were used in these two studies. The first dog study evaluated the model with the partially inserted implants and the second dog study evaluated a bone morphogenetic protein S 300 cocktail (BMP S300). In all studies threaded commercially pure titanium implants were used. Evaluation of the osseointegration of the implants was performed by resonance frequency analysis (4 studies), removal torque test (3 studies), dual energy X-ray analysis (one study), histomorphometric analysis on undecalcified ground sections (all studies) and image access analysis on microradiographs (one study).ResultsThe results indicate that systemically delivered human growth hormone may enhance the initial implant integration and that local delivery of FGF-4s may stimulate bone formation around titanium implants. However, it seemed that EMD, BMP-7 and BMP S300 failed to stimulate bone formation around titanium implants in the used models.ConclusionWithin the limits of the studies of the present thesis growth factors locally applied in conjunction with press fit placed titanium implants does not seem to contribute to substantially improved implant integration. Small positive effects were demonstrated after systemically delivered hGH and FGF-4s pre-treated bone. However, the present author has not at all been convinced that external supply by growth factors are effective in experimental press fit models as those used in the present study. It is quite possible that inherent growth factor are sufficient to stimulate bone formation around press fit titanium implants and an external addition of growth factors may not result in substantially reinforced bone volumes. This assumption implies that growth factors may be of little use in the ordinary clinical situation.
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25.
  • Franke Stenport, Victoria, 1970, et al. (författare)
  • Onlay and inlay bone grafts with platelet-rich plasma: histologic evaluations from human biopsies.
  • 2011
  • Ingår i: Journal of oral and maxillofacial surgery : official journal of the American Association of Oral and Maxillofacial Surgeons. - : Elsevier BV. - 1531-5053 .- 0278-2391. ; 69:4, s. 1079-85
  • Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
    • The aim of the present study was to histomorphometrically evaluate biopsies from 1) sinus inlay bone grafts prepared with or without platelet-rich plasma (PRP) and 2) onlay bone grafts in the anterior maxilla with particulate bone and PRP or block bone without PRP after 3 months.
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26.
  • Franke Stenport, Victoria, 1970, et al. (författare)
  • Precipitation of calcium phosphate in the presence of albumin on titanium implants with four different possibly bioactive surface preparations. An in vitro study
  • 2008
  • Ingår i: Journal of Materials Science: Materials in Medicine. - : Springer Science and Business Media LLC. - 0957-4530 .- 1573-4838. ; 19:12, s. 3497-3505
  • Tidskriftsartikel (refereegranskat)abstract
    • The aim of the present study was to compare the nucleating behaviour on four types of bioactive surfaces by using the simulated body fluid (SBF) model with the presence albumin. Titanium discs were blasted (B) and then prepared by alkali and heat treatment (AH), anodic oxidation (AO), fluoridation (F), or hydroxyapatite coating (HA). The discs were immersed in SBF with 4.5 mg/ml albumin for 3 days, 1, 2, 3 and 4 weeks and analysed with scanning electron microscopy/energy dispersive X-ray analysis (SEM/EDX) and X-ray photoelectron spectroscopy (XPS). Topographic surface characterisation was performed with a contact stylus profilometer. The results demonstrated that the bioactive surfaces initiated an enhanced calcium phosphate (CaP) formation and a more rapid increase of protein content was present on the bioactive surfaces compared to the blasted control surface. The observation was present on all bioactive surfaces. The fact that there was a difference between the bioactive surfaces and the blasted control surface with respect to precipitation of CaP and protein content on the surfaces support the fact that there may be biochemical advantages in vivo by using a bioactive surface.
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27.
  • Franke Stenport, Victoria, 1970, et al. (författare)
  • Precipitation of Calcium Phosphates in the Presence of Collagen Type I on Four Different Bioactive Titanium Surfaces: an in Vitro Study.
  • 2015
  • Ingår i: Journal of oral & maxillofacial research. - : Stilus Optimus. - 2029-283X. ; 6:4
  • Tidskriftsartikel (refereegranskat)abstract
    • To compare the properties of calcium phosphate precipitation on four different bioactive surface preparations and one control surface in the simulated body fluid model with added collagen type I.Blasted titanium discs were treated with four different surface modifications, alkali and heat, sodium fluoride, anodic oxidation and hydroxyapatite coating. The discs were divided into five groups where one group, the blasted, served as control. The discs were immersed in simulated body fluid and collagen for 24 h, 3 days, 1 week and 2 weeks and then analysed by optical interferometry, scanning electron microscopy/energy dispersive X-ray analysis and X-ray photoelectron spectroscopy.All surfaces show small precipitates after 3 days which with longer immersion times increase. After 2 weeks the surfaces were completely covered with precipitates, and Ca/P ratios were approximately 1.3, independently on surface preparation. The fluoridated discs showed significantly (P ≤ 0.05) higher degree of CaP after one week of immersion as compared to the other surface preparations. The collagen type I content increased with time, as reflected by increased nitrogen content.The results from this study indicate that a fluoridated titanium surface may favour precipitation of calcium phosphate in the presence of collagen type I, as compared to the other surface treatments of the present study.
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28.
  • Franke Stenport, Victoria, 1970, et al. (författare)
  • Systemically administered human growth hormone improves initial implant stability: an experimental study in the rabbit.
  • 2001
  • Ingår i: Clinical implant dentistry and related research. - 1523-0899. ; 3:3, s. 135-41
  • Tidskriftsartikel (refereegranskat)abstract
    • PURPOSE: This study was an investigation to determine whether human growth hormone (hGH) continuously administered to rabbits may improve implant integration in bone. MATERIALS AND METHODS: Thirty-two commercially pure titanium (c.p. Ti) implants were inserted in the tibiae of 16 rabbits. Human growth hormone (0.3 U/kg/d) or sodium chloride (NaCl) was administered by subcutaneous pumps. Insulin-like growth factor-1 (IGF-1) levels in blood were measured. Two biomechanical tests were performed: (1) every second week resonance frequency analysis (RFA) was used to investigate implant stability or stiffness at the interface and, after 8 weeks of follow-up, (2) removal torque (a measure of implant integration and stability) was registered. Further evaluation was performed by dual energy x-ray analysis (DEXA), to evaluate bone mineral density, and histomorphometric analysis of tissue-to-implant integration on undecalcified cut and ground sections. RESULTS: A difference in implant stability was detected with the RFA technique after 2 weeks and 8 weeks in favor of the hGH-treated rabbits. No significant differences were detected with removal torque, DEXA, and histomorphometric measurements. The blood test demonstrated antibody development in the rabbits treated with hGH after 4 weeks. CONCLUSION: Growth hormone has an initial beneficial effect on implant integration; however, owing to rapid antibody formation, this study did not demonstrate whether this effect remains in the long term.
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29.
  • Franke-Stenport, Victoria, et al. (författare)
  • Titanium implants and BMP-7 in bone : an experimental model in the rabbit
  • 2003
  • Ingår i: Journal of materials science. Materials in medicine. - 0957-4530 .- 1573-4838. ; 14:3, s. 247-254
  • Tidskriftsartikel (refereegranskat)abstract
    • This study evaluates the effect of rhBMP-7/OP-1 on the osseointegration of commercially pure titanium implants in an experimental implant model in rabbits. Threaded titanium implants with two transverse parallel canals were inserted in the femur and tibia of rabbits. The canals were filled with, 10 microg of BMP-7/collagen carrier, pure collagen carrier or were left empty as a control. The stiffness of the implant fixation was evaluated by Resonance Frequency Analysis (RFA) at baseline and four weeks postoperatively. Percentage of bone ingrowth in the canals was measured on microradiographs. Histomorphometry along the threaded part of the implants was performed on 15 microm thin sections. The results from the RFA demonstrated a higher mean value for the BMP-7 treated implants in the tibia than the carrier treated implants but not compared to the control implants. The control implants in the tibia demonstrated more bone ingrowth in the upper canal than to the carrier or the BMP-7 treated implants. Apart from these differences there were no significant effects of BMP. In this study BMP-7 did not contribute to any substantially improved bone anchorage of titanium implants.
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30.
  • Ghiasi, Peyman (författare)
  • Studies on maxillary overdentures : implant- and prosthesis survival, cost analysis and patient-reported outcomes
  • 2022
  • Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
    • Edentulism is a debilitating condition which may negatively affect quality of life, particularly in relation to nutritional and social health, speech, and poor facial appearance. Prosthetic options available range from conventional complete dentures to implant-supported overdentures (ISODs) and implant-supported full arch fixed partial dentures (ISFAFDPs). The choice of treatment is connected to the patient's general health, oral status, preferences and financial means. From the point of view of the treatment provider, there is a lack of evidence to support choice of treatment, as information from randomised clinical trials is sparse. This is particularly true when it comes to cost analysis and patient-reported outcome measures (PROMs). There is consensus today that an implant-supported overdenture is a valid treatment option for the edentulous mandible, but the same recommendation cannot be made for maxillary overdentures due to a lack of evidence.The present study investigates implant-supported maxillary overdentures regarding implant and prosthesis survival, costs and PROMs in comparison to fixed implant-supported prostheses.The thesis comprises four studies.Study I analysed implant and prosthesis failure rates with implant-supported maxillary overdentures in a systematic review. The cumulative survival rate (CSR) for the implants and the prostheses was 70.4% and 79.8%, respectively. The main finding was that patients with few implants presented higher prosthesis failure rates than patients with more implants per prosthesis.Of the most commonly used attachment systems, the ball/O-ring and the Ceka were the ones with the highest rates of patients with at least one implant failure. Most of the failures happened within the first year after installation for both implants (52.1%) and prostheses (41.8%).Study II, a retrospective analysis, compared the clinical outcomes of implantsupported overdentures (ISODs) with either bar-clip or ball attachments. The results showed that all ISOD failures resulted from loss of implants. The bar-clip system resulted in more complications than the ball attachment system, suggesting that ISODs with the bar-clip system may necessitate a greater number of appointments and chair time for adjustments, thus increasing the maintenance costs for the patient.Studies III and IV were based on a prospective clinical trial comparing different implant-supported prosthetic rehabilitations for the edentulous maxilla: implantsupported full-arch fixed partial dentures on 4 or 6 implants (ISFAFDP 4 orISFAFDP 6) versus maxillary overdentures on 2 implants.Study III is a comparative cost analysis, the results of which showed that all implants and restorations were in function at follow-up after the first year, i.e., the survival rate was 100%. Initial costs, i.e., cost of prostheses at delivery, were higher for ISFAFDP 6 and ISFAFDP 4 due to the higher number of implants and higher cost of materials and fees. There were no statistically significant differences in post-treatment costs between the groups.In study IV, patient-reported outcomes regarding aesthetics and function were compared. The results showed that all patients, irrespective of group, showed improved patient-reported outcomes from before treatment to the one-year follow-up. There were no significant differences between groups regarding functional status of the masticatory system (Jaw Functional Limitation Scale -JFLS parameters) or how patients perceive their dental and Orofacial Aesthetic Scale (OAS), and only minor differences between the two groups with fixed restorations regarding patients’ perception of the social impact of oral disorders on their well-being (Oral Health Impact Profile - OHIP).
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31.
  • Göransson, Anna, 1970, et al. (författare)
  • An in vitro comparison of possibly bioactive titanium implant surfaces.
  • 2009
  • Ingår i: Journal of Biomedical Materials Research Part A. - : Wiley. - 1552-4965 .- 1549-3296. ; 88:4, s. 1037-1047
  • Tidskriftsartikel (refereegranskat)abstract
    • The aim of the study was to compare Ca and P formation (CaP) and subsequent bone cell response of a blasted and four different possibly bioactive commercially pure (cp) titanium surfaces; 1. Fluoride etched (Fluoride), 2. Alkali-heat treated (AH), 3. Magnesium ion incorporated anodized (TiMgO), and 4. Nano HA coated and heat treated (nano HA) in vitro. Furthermore, to evaluate the significance of the SBF formed CaP coat on bone cell response. The surfaces were characterized by Optical Interferometry, Scanning Electron Microscopy (SEM) and X-ray Photoelectron Spectroscopy (XPS). CaP formation was evaluated after 12, 24 and 72 h in simulated body fluid (SBF). Primary human mandibular osteoblast-like cells were cultured on the various surfaces subjected to SBF for 72 h. Cellular attachment, differentiation (osteocalcin) and protein production (TGF-beta(1)) was evaluated after 3 h and 10 days respectively. Despite different morphological appearances, the roughness of the differently modified surfaces was similar. The possibly bioactive surfaces gave rise to an earlier CaP formation than the blasted surface, however, after 72 h the blasted surface demonstrated increased CaP formation compared to the possibly bioactive surfaces. Subsequent bone cell attachment was correlated to neither surface roughness nor the amount of formed CaP after SBF treatment. In contrast, osteocalcin and TGF-beta(1) production were largely correlated to the amount of CaP formed on the surfaces. However, bone response (cell attachment, osteocalcin and TGF-F production) on the blasted controls were similar or increased compared to the SBF treated fluoridated, AH and TiMgO surface. (c) 2008 Wiley Periodicals, Inc. J Biomed Mater Res, 2008.
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32.
  • Jemt, Torsten, 1950, et al. (författare)
  • Associations Between Early Implant Failure, Patient Age, and Patient Mortality: A 15-Year Follow-Up Study on 2,566 Patients Treated with Implant-Supported Prostheses in the Edentulous Jaw
  • 2017
  • Ingår i: International Journal of Prosthodontics. - : Quintessence Publishing. - 0893-2174. ; 30:2, s. 189-197
  • Tidskriftsartikel (refereegranskat)abstract
    • Purpose: The aim of this study was to report the distribution of patients with early implant failures after implant treatment in the edentulous jaw with regard to age at surgery and association with patient mortality over a 15-year period. Materials and Methods: All consecutively treated patients treated in the edentulous jaw at a single specialist clinic from 1986 to 1997 were included and followed up for 1 year for implant failures and for 15 years with regard to patient mortality. Patients were arranged into age groups, and life tables for patients and reference groups of patients with comparable age (based on national population data) were calculated. Log rank test was used to test differences in patient survival between those with reported early implant failures and those with no early failures. Mantel-Haenszel chi-square test was used to test association between proportions of implant failures and age groups. Results: A total of 55 patients were excluded because they were not living in Sweden (nonresidents/emigrated). Altogether, 2,566 patients were included, with a mean age of 65 years (SD: 11). Of these, 988 patients were deceased during the 15 years of followup (38%), and 291 presented an early implant failure (11.3%), most of them before prosthesis placement (72%). Patients with early implant failures presented higher mortality rates than patients with no failures (P < .05), and failure rates decreased consistently from younger to higher age groups (P < .05). Conclusion: Patients in the younger age groups showed an increased mortality compared with the reference group (P < .05) and a higher prevalence of early failures compared with older patients (P < .05). Older patients showed an opposing pattern of lower mortality compared with reference groups of comparable age (P < .05), but both younger and older patients with early failures showed a higher mortality compared to patients with no failures (P < .05).
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33.
  • Jemt, Torsten, 1950, et al. (författare)
  • Could Age at Surgery Be Associated with Early Mortality After Implant Surgery? A Retrospective Study of 3,877 Edentulous Patients
  • 2022
  • Ingår i: International Journal of Oral & Maxillofacial Implants. - : Quintessence Publishing. - 0882-2786. ; 37:1, s. 128-134
  • Tidskriftsartikel (refereegranskat)abstract
    • Purpose: Knowledge of the early mortality patterns in edentulous implant patients is limited. This study aimed to report patient mortality within the first year after surgery and compare the cause of death with preexisting conditions reported before surgery. Materials and Methods: In this retrospective cohort study, data from the Swedish National Death Register on patients, consecutively treated in the edentulous arch between 1986 and 2013, were compared with information from the patient files regarding the preexisting health conditions of the deceased patients. One-year survival rates were calculated and compared with expected mortality in a Swedish reference population based on three age groups: young ( 45 years of age), middle-aged (45 to 64 years of age), and old patients ( 64 years of age). Proportions of mortality between study groups and reference populations were tested by means of a log-rank test, and agreement between diagnoses before surgery and cause of death was tested by means of kappa test. Results: Altogether, 3,877 patients were included, of whom 60 patients died within 1 year after implant surgery (1.5%). The expected mortality in the Swedish reference population was 2.1% (P < .05). Mortality was higher for middle-aged (P = .02) but lower for old patients (P = .0001) compared with the Swedish reference populations. Eight of the deceased patients (13%) had no preexisting conditions, while 48 patients reported a health diagnosis before implant surgery. The most common of these were related to the circulatory system (ICD 10-I), which was the cause of death for 30 patients. A "none to slight agreement" between presurgical diagnoses and cause of death was observed in the population (kappa: 0.152). Conclusion: Edentulous implant patients presented overall lower mortality than expected in the general population during the first year after surgery. However, middle-aged patients showed a higher proportion of deceased patients compared with control people of the same age. Cardiovascular diseases were the cause of death in 50% of the group, and the agreement between presurgical and cause of death diagnoses was poor.
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34.
  • Jemt, Torsten, 1950, et al. (författare)
  • Early Implant Failures Related to Individual Surgeons: An Analysis Covering 11,074 Operations Performed during 28 Years
  • 2016
  • Ingår i: Clinical Implant Dentistry and Related Research. - : Wiley. - 1523-0899. ; 18:5, s. 861-872
  • Tidskriftsartikel (refereegranskat)abstract
    • Background: Compared with knowledge on patient and implant component factors, little knowledge is available on surgeons' role in early implant failures. Purpose: To report incidence of early implant failures related to total number of operations performed by individual surgeons. Materials and Methods: Early implant failures (21 year of implant prosthesis function) were reported after a total of 11,074 implant operations at one specialist clinic during 28 years of surgery. Altogether, 8,808 individual patients were treated by 23 different dentists, of whom 21 surgeons were specialists in oral surgery or periodontology. Recorded failures were related to total numbers of performed operations per surgeon, followed by statistical comparisons (chi(2)) between surgeons with regard to type of treated jaw and implant surface. Results: Altogether, 616 operations were recorded with early implant failures (5.6%), most often observed in edentulous upper jaws after placing implants with a turned surface (p <.05). Significant differences between surgeons, gender of surgeon, type of treated jaws by the surgeon, and implant surface used by the surgeon could be observed (p <.05). Conclusions: Early implant failures are complex, multifactorial problems associated with many aspects in the surgical procedure. A stochastic variation of failures for individual surgeons could be observed over the years. Different levels of failure rate could be observed between the surgeons, occasionally reaching significant levels as a total or for different jaw situations (p <.05). The surgeons reduced their failure rates when using implants with moderately rough surfaces (p <.5), but the relationship of failure rate between the surgeons was maintained.
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35.
  • Jemt, Torsten, 1950, et al. (författare)
  • Implant treatment with fixed prostheses in the edentulous maxilla. Part 1: implants and biologic response in two patient cohorts restored between 1986 and 1987 and 15 years later.
  • 2011
  • Ingår i: The International journal of prosthodontics. - 0893-2174. ; 24:4, s. 345-55
  • Tidskriftsartikel (refereegranskat)abstract
    • Purpose: Implant treatment has been performed for more than 45 years, but there is still limited knowledge on how treatment outcomes are changing over time. The aim of this study was to report and compare the treatment outcomes of two patient cohorts from the same clinic, rehabilitated with fixed implant prostheses in the edentulous maxilla between 1986 and 1987 (early) and 2001 to 2004 (late). Materials and Methods: The early group included 76 edentulous patients who were consecutively provided with 450 turned Branemark System implants; the late group included 109 edentulous patients provided with 360 turned and 310 TiUnite Branemark System implants. Both groups were followed and evaluated clinically and radiographically for 5 years according to similar protocols. Results: Altogether, 37 patients (20%) were lost to follow-up over 5 years; more patients were noncompliant in the late group (P < .05). The 5-year overall implant cumulative survival rates were 93.4% and 97.3% for the early and late groups, respectively. In the early group, significantly more turned implants failed before prosthesis insertion compared to the outcome of TiUnite implants in the late group (P < .05). Mean bone loss was comparable for the early and late groups during the 5 years of follow-up (0.5 ± 0.46 and 0.7 ± 0.76 mm, respectively), but more patients presented at least 1 implant with more than 2 mm of bone loss during the follow-up period in the late group (P < .05). Mucosal hyperplasia and inflammation showed a trend of higher frequency at implants in the early group of patients (P > .05). Conclusion: Implant treatment was more predictable before loading in the late group of patients, related to the change in the implant surface (P < .05). On the other hand, it was observed that the prevalence of patients with more bone loss at at least 1 implant (> 2 mm) was higher in the late group (P < .05). This could possibly be attributed to a more bioactive implant surface and shorter healing period before implant surgery in the late group. Int J Prosthodont 2011;24:345-355.
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36.
  • Jemt, Torsten, 1950, et al. (författare)
  • Implant treatment with fixed prostheses in the edentulous maxilla. Part 2: prosthetic technique and clinical maintenance in two patient cohorts restored between 1986 and 1987 and 15 years later.
  • 2011
  • Ingår i: The International journal of prosthodontics. - 0893-2174. ; 24:4, s. 356-62
  • Tidskriftsartikel (refereegranskat)abstract
    • Purpose: Implant treatment using osseointegrated implants has been performed for more than 40 years, but limited knowledge is available on how treatment outcomes have changed over time. The aim of this study was to report and compare the prosthetic treatment outcomes from two patient cohorts provided with fixed implant prostheses in the edentulous maxilla between 1986 and 1987 (early) and 2001 to 2004 (late) at the same clinic. Materials and Methods: The two groups of patients comprised 76 and 109 edentulous patients consecutively provided with 450 and 670 Branemark System implants and fixed screw-retained prostheses, respectively. Both groups were followed for 5 years with regard to prosthetic treatment, clinical maintenance, and complications. Results: Altogether, 37 patients (20%) were lost to follow-up during the 5 years, and more patients were noncompliant in the late group (P < .05). Prosthetic treatment was performed using significantly less chair time in the late group (P < .05), and 22 and 68 patients were followed for 5 years without any reported complications in the early and late groups, respectively (P < .05). The 5-year prosthesis cumulative survival rate was 97.1% in the early group and 100.0% in the late group. Patients in the late group presented fewer problems with diction and veneer fractures, and fewer patients had their prostheses temporarily removed for adjustments (P < .05). Conclusion: Prosthetic treatment and maintenance of implant-supported fixed prostheses improved significantly between the groups. Int J Prosthodont 2011;24:356-362.
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37.
  • Jemt, Torsten, 1950, et al. (författare)
  • Incidence of First Implant Failure: A Retroprospective Study of 27 Years of Implant Operations at One Specialist Clinic
  • 2015
  • Ingår i: Clinical Implant Dentistry and Related Research. - : Wiley. - 1523-0899 .- 1708-8208. ; 17
  • Tidskriftsartikel (refereegranskat)abstract
    • © 2015 Wiley Periodicals, Inc. Background: Even though there are many studies available reporting on implant failures, there are few studies that follow implant failures over time in large populations. Purpose: The purpose of this article is to present an overview of the annual incidence of reported implant failures for patients and operations over a 28-year period. Materials and Methods: A total of 8,528 patients were consecutively provided with 39,077 implants in 10,719 implant operations during a 27-year period (1986-2012) at one specialist clinic. All patients with reported failures of implants during a 28-year routine follow-up period (1986-2013) were included, and data from the patients' files were retrieved and reported. Results: Altogether, 857 patients (882 jaws/operations) were identified with one or more failures (10.0% of patients/8.5% of operations). Mean annual incidence of first failure showed obvious variations between years, even between seemingly clinically similar situations. However, incidence of first implant failure was higher for upper than lower jaws (p<.05), within 1 year of surgery (69%) than after 1 year (p<.05), and for implants with a turned surface compared with implants with a moderately rough surface (p<.05). Conclusions: With regard to annual failure incidence in relation to total number of operations over time, obvious variations in failure rate can be observed between seemingly similar clinical situations, as well as significant differences in incidence of first implant failure between the first year after surgery and later time points, between upper and lower jaws using implants with turned surfaces, and between operations to install implants with turned surfaces and those to install implants with moderately rough surfaces.
  •  
38.
  • Jemt, Torsten, 1950, et al. (författare)
  • Patterns of Mortality in Patients Treated with Dental Implants: A Comparison of Patient Age Groups and Corresponding Reference Populations
  • 2015
  • Ingår i: International Journal of Prosthodontics. - : Quintessence Publishing. - 0893-2174. ; 28:6, s. 569-576
  • Tidskriftsartikel (refereegranskat)abstract
    • Purpose: Little is known about the relationship between implant patient mortality compared to reference populations. The aim of this study was to report the mortality pattern in patients treated with dental implants up to a 15-year period, and to compare this to mortality in reference populations with regard to age at surgery, sex, and degree of tooth loss. Materials and Methods: Patient cumulative survival rate (CSR) was calculated for a total of 4,231 treated implant patients from a single clinic. Information was based on surgical registers in the clinic and the National Population Register in Sweden. Patients were arranged into age groups of 10 years, and CSR was compared to that of the reference population of comparable age and reported in relation to age at surgery, sex, and type of jaw/dentition. Results: A similar, consistent, general relationship between CSR of different age groups of implant patients and reference populations could be observed for all parameters studied. Completely edentulous patients presented higher mortality than partially edentulous patients (P < .05). Furthermore, implant patients in younger age groups showed mortality similar to or higher than reference populations, while older patient age groups showed increasingly lower mortality than comparable reference populations for edentulous and partially edentulous patients (P < .05). Conclusion: A consistent pattern of mortality in different age groups of patients compared to reference populations was observed, indicating higher patient mortality in younger age groups and lower in older groups. The reported pattern is not assumed to be related to implant treatment per se, but is assumed to reflect the variation in general health of a selected subgroup of treated implant patients compared to the reference population in different age groups.
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39.
  • Kassapidou, Maria, et al. (författare)
  • Cobalt-chromium alloys fabricated with four different techniques: Ion release, toxicity of released elements and surface roughness
  • 2020
  • Ingår i: Dental Materials. - : Elsevier BV. - 0109-5641 .- 1879-0097. ; 36:11
  • Tidskriftsartikel (refereegranskat)abstract
    • Objective. To investigate the metal ion release, surface roughness and cytoxicity for Co-Cr alloys produced by different manufacturing techniques before and after heat treatment. In addition, to evaluate if the combination of materials affects the ion release. Methods. Five Co-Cr alloys were included, based on four manufacturing techniques. Commercially pure titanium, CpTi grade 4 and a titanium alloy were included for comparison. The ion release tests involved both Inductive Coupled Plasma Optical Emission Spectrometry and Inductive Coupled Plasma Mass Spectrometry analyses. The surface analysis was conducted with optical interferometry. Cells were indirectly exposed to the materials and cell viability was evaluated with the MTT (3-(4.5-dimethylthiazol-2-yl)-2.5-diphenyltetrazolium bromide) method. Results. All alloys showed a decrease of the total ion release when CpTi grade 4 was present. The total ion release decreased over time for all specimens and the highest ion release was observed from the cast and milled Co-Cr alloy in acidic conditions. The cast and laser-melted Co-Cr alloy and the titanium alloy became rougher after heat treatment. All materials were within the limits of cell viability according to standards. Significance. The ion release from Co-Cr alloys is influenced by the combination of materials, pH and time. Surface roughness is influenced by heat treatment. Furthermore, both ion release and surface roughness are influenced by the manufacturing technique and the alloy type. The clinical implication needs to be further investigated. (C) 2020 The Academy of Dental Materials. Published by Elsevier Inc.
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40.
  • Kassapidou, Maria, et al. (författare)
  • Cobalt-chromium alloys in fixed prosthodontics : Investigations of mechanical properties and microstructure
  • 2023
  • Ingår i: The Journal of prosthetic dentistry (Print). - : Elsevier. - 0022-3913 .- 1097-6841. ; 130:2, s. 255.e1-255.e10
  • Tidskriftsartikel (refereegranskat)abstract
    • STATEMENT OF PROBLEM: Cobalt-chromium (Co-Cr) alloys possess beneficial mechanical properties because alloys, even in thin sections, can resist high mastication forces and exhibit an acceptable bond to the surface porcelain layer. Traditional manufacturing techniques of Co-Cr alloys such as casting have been replaced with newer fabrication techniques, such as milling, laser melting, and presintered milling. Despite scarce documentation, these new manufacturing techniques are being used to fabricate dental and implant constructions.PURPOSE: This in vitro study investigates the hardness, yield strength, elastic modulus, and microstructure of the most commonly used Co-Cr alloys for fixed prosthodontics based on manufacturing technique. In addition, this study investigates the effect of heat treatment on the mechanical properties and microstructure of these materials.MATERIAL AND METHODS: Five Co-Cr alloys were included (dumbbell and rectangular shaped) based on four manufacturing techniques: cast, milled, laser melted, and presintered milled. Commercially pure titanium grade 4 and titanium-6 aluminum-4 vanadium ELI (extra low interstitial) were included for comparison, and yield strength and elongation after fracture were evaluated. The specimens were tested for hardness using the Vickers test and for elastic modulus using a nondestructive impulse excitation technique. The microstructure of selected specimens was analyzed using focused ion beam-scanning electron microscopy (FIB-SEM) and energy dispersive X-ray spectroscopy (EDS).RESULTS: The mechanical properties depend on the manufacturing technique used; the laser-melted and presintered Co-Cr specimens demonstrated the highest mechanical properties, followed by the milled and cast groups. Both the laser-melted and the presintered milled Co-Cr specimens showed smaller grain size compared with the cast and milled Co-Cr specimens. The titanium-6 aluminum-4 vanadium ELI demonstrated higher hardness and yield strength compared to commercially pure titanium grade 4. No major differences were observed for the selected materials regarding the mechanical properties and microstructural appearance after heat treatment.CONCLUSIONS: The laser melting and presintered milling techniques produced higher mechanical properties compared with the cast and milled Co-Cr. These findings were confirmed through microstructural analysis with respect to the grain size, precipitation, and number of pores.
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41.
  • Kassapidou, Maria, et al. (författare)
  • Cobalt-chromium alloys in fixed prosthodontics in Sweden
  • 2017
  • Ingår i: Acta Biomaterialia Odontologica Scandinavica. - : Informa UK Limited. - 2333-7931. ; 3:1, s. 53-62
  • Tidskriftsartikel (refereegranskat)abstract
    • Aim: The aim of this study was to compile the usage of Co-Cr alloys in fixed prosthodontics (FP) among dental laboratories in Sweden.Methods: From March to October 2015, questionnaires were sent to 542 registered dental laboratories in Sweden. The questionnaires were divided in two parts, one for fixed dental-supported prosthodontics (FDP) and one for fixed implant-supported prosthodontics (FIP). Reminders were sent three times.Results: In total of 542 dental laboratories, 55% answered the questionnaires. Most dental laboratories use Co-Cr in FP, 134 (74%) in FDP and 89(66%) in FIP. The laboratories used Co-Cr alloys of various compositions in the prostheses, 35 for FDP and 30 for FIP. The most commonly used Co-Cr alloys for tooth-supported FDPs were (a) Wirobond® 280, (b) Cara SLM and (c) Wirobond® C. For implant-supported frameworks the frequently used alloys were: (a) Cara SLM, (b) Cara Milled and (c) Wirobond® 280. Except for the difference in composition of these alloys, they were also manufactured with various techniques. In tooth-supported prostheses the dominating technique was the cast technique while newer techniques as laser-sintering and milling were more commonly reported for implant-supported constructions. A fourth technique; the ‘pre-state’ milling was reported in FDP.Conclusion: More than 30 different Co-Cr alloys were reported as being used in FP. Thus, there is a need for studies exploring the mechanical and physical behavior and the biological response to the most commonly used Co-Cr alloys.
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42.
  • Kassapidou, Maria, et al. (författare)
  • Inflammatory Response to Cobalt-Chromium Alloys Fabricated With Different Techniques
  • 2021
  • Ingår i: Journal of Oral & Maxillofacial Research. - : UAB Stilus Optimus. - 2029-283X. ; 12:4
  • Tidskriftsartikel (refereegranskat)abstract
    • Objectives: To explore the in vitro cytokine expression of human peripheral blood mononuclear cells exposed to cobalt-chromium alloys, manufactured with different techniques, in comparison with commercially pure titanium grade 4 and titanium alloy grade 23.Material and Methods: Peripheral blood mononuclear cells (PBMC) were collected from 10 healthy blood donors and exposed to machine-ground coin-shaped: (a) cobalt-chromium (Co-Cr) specimens (n = 5) manufactured by four techniques, i.e. cast, milled, laser melted and presintered milled; (b) commercially pure titanium grade 4; and (c) titanium alloy grade 23. The cells were cultured for 4, 24 and 72 hours followed by investigations of pro- and anti-inflammatory cytokine release using Bio-Plex Pro (TM).Results: In general, the PBMC produced significantly more cytokines when exposed to the cast and presintered milled Co-Cr materials compared to laser melted, milled Co-Cr and titanium materials.Conclusions: Within the limitation of the present study, it may be suggested that cast and presintered milled cobalt-chromium alloys provoke a stronger inflammatory response compared to milled and laser melted cobalt-chromium alloys and titanium materials.
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43.
  • Kowar, J., et al. (författare)
  • Causes of Death in Implant Patients Treated in the Edentulous Jaw: A Comparison between 2098 Deceased Patients and the Swedish National Cause of Death Register
  • 2019
  • Ingår i: International Journal of Dentistry. - : Hindawi Limited. - 1687-8728 .- 1687-8736.
  • Tidskriftsartikel (refereegranskat)abstract
    • Background. Previous research has reported an association between tooth loss and patient mortality, while the cause of death has not been elucidated. Objective. The purpose was to describe and compare the cause of death in implant patients treated consecutively in the edentulous arch with a reference population. Methods. Altogether, 3902 patients were included between 1986 and 2014. Data on the causes of death for deceased patients were compared to the Swedish National Cause of Death Register for a comparable time period. Standardised mortality ratios (SMRs) were calculated based on gender and age and tested for statistical significance. Results. Most deceased patients (2,098) died from diseases in the circulatory system (CVD; 42%) and from cancers (26%). SMR indicated a generally increased mortality (total group) compared to the reference population during inclusion (P < 0.05; 1986-2014). Patients treated early (1986-1996) showed a lower SMR compared to patients treated later (P < 0.05; 1997-2014) especially related to CVDs. Younger patients (<60 years at surgery) showed an increased mortality due to CVDs when treated late (1997-2014; SMR = 5.4, P < 0.05). Elderly patients (>79 years at surgery) showed a significantly lower mortality in almost all observed causes of death (1986-2014; P < 0.05) with also a significantly lower mortality due to CVDs during the early period (1986-1996; SMR = 0.3, P < 0.05). Conclusion. An overall increased mortality was observed for the edentulous implant patient compared to the reference population. Elderly patients (>79 years) showed significantly lower mortality for all causes of death independent of the time period of implant surgery. Younger patients (<60 years) present an increased risk for early mortality related to CV D. SMR for all causes of death increased for patients treated late (1997-2014) as compared to patients treated early (1986-1996).
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44.
  • Kowar, Jan, 1972, et al. (författare)
  • Long-term performance of implants with moderately rough anodized surface supporting single-tooth restorations: A retrospective analysis with an up to 15-year follow-up
  • 2023
  • Ingår i: Clinical Oral Implants Research. - : Wiley. - 0905-7161 .- 1600-0501. ; 34:4, s. 367-377
  • Tidskriftsartikel (refereegranskat)abstract
    • ObjectivesThis retrospective study aimed to evaluate long-term clinical and radiologic performance of anodized surface implants supporting single implant restorations. Materials and MethodsPatients who received at least one anodized surface implant for a single-tooth restoration between 2003 and 2004 in the Branemark clinic (Goteborg, Sweden) were included in the study. The assessed outcomes included implant survival, biological and technical complications, as well as marginal bone levels (MBL) based on radiographs. Baseline data on patient demographics, implant placement, and surgery details were also collected. The cumulative survival rate (CSR) was calculated using the Kaplan-Meier survival analysis. ResultsThe study included 97 patients with 129 implants. Mean patient age at the time of implant placement was 31.7 +/- 16.4 years. All implants were placed in a two-stage approach with delayed loading. The last follow-up visit was on average 13.4 +/- 4.8 years after implant insertion. Three implants failed, yielding the implant-level 15-year CSR of 97.4%. Majority of the implants had no biological (70.5%) nor technical (81.4%) complications. The mean MBL was -1.0 +/- 0.7 mm (n = 101) at prosthetic placement and -1.8 +/- 1.0 mm (n = 80) at the last follow-up, while the mean marginal bone loss (MBL) from prosthetic placement to last follow-up was 0.6 +/- 1.1 mm (n = 65). ConclusionsModerately rough anodized implants have shown favorable long-term outcomessingle-tooth indication, with high survival and a low rate of technical complications. Furthermore, long-term studies are needed to present longitudinal data on peri-implantitis.
  •  
45.
  • Kowar, J., et al. (författare)
  • Mortality in Edentulous Patients: A Registry-Based Cohort Study in Sweden Comparing 8463 Patients Treated with Removable Dentures or Implant-Supported Dental Prostheses
  • 2021
  • Ingår i: International Journal of Dentistry. - : Hindawi Limited. - 1687-8728 .- 1687-8736. ; 2021
  • Tidskriftsartikel (refereegranskat)abstract
    • Objectives. The purpose of this study was to investigate if edentulism is associated with all-cause mortality. The aims were to analyze the association between age, socioeconomic factors, and mortality in edentulous patients treated with either removable dentures or implant-supported prostheses. Methods. All patients who became edentulous according to the Swedish Social Insurance Agency (SSIA) between 2009 and 2013 (N = 8463) were analyzed regarding prosthetic treatment, age, gender, and socioeconomic status. The patients were divided into two groups, depending on whether they were treated with dental implants (implant group; IG) or with conventional removable dentures (denture group; DG). Data on mortality for all included individuals were obtained from the Swedish National Cause of Death Register and compared to a reference population. Cumulative survival rates were calculated, and a multivariable regression analysis for the included variables was performed. Results. Between 2009 and 2018, 2192 of the patients (25.9%) were treated with implant-supported dental prostheses (IG) and 6271 patients (74.1%) were treated with removable dentures without support of dental implants (DG). Altogether 2526 patients (30%) died until December 31, 2019, and the overall mortality was significantly higher for the DG compared to the IG during follow-up (p<0.001). Younger edentulous patients (<= 59 years) presented a higher mortality than the reference population, while implant patients over 79 years of age demonstrated a lower mortality. The final results from the multivariable logistic analysis showed that lower equalized disposable income (EDI) and the choice of conventional removable dentures are the most important factors for increased patient mortality (p<0.001). Conclusions. Edentulous patients have an overall higher mortality compared to a reference population. Low socioeconomic status increases all-cause mortality. Individuals treated with dental implants show statistically significant lower 10-year mortality compared to patients treated with conventional removable dentures, regardless of socioeconomic status.
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46.
  • Kowar, Jan, 1972, et al. (författare)
  • Mortality patterns in partially edentulous and edentulous elderly patients treated with dental implants.
  • 2014
  • Ingår i: The International journal of prosthodontics. - : Quintessence Publishing. - 0893-2174. ; 27:3, s. 250-6
  • Tidskriftsartikel (refereegranskat)abstract
    • An association between oral health, number of teeth, and mortality has been reported in the literature, but limited knowledge is available on mortality in elderly partially edentulous and edentulous patients treated with implants.The aim of this retrospective study was to compare the mortality pattern in elderly patients (80 years or older) who were provided with implants and were partially or completely edentulous.Between 1986 and 2003, a total of 266 elderly patients with a mean age of 83.0 years at the time of implant placement were included. The patients were provided with 1,384 Brånemark System implants (Nobel Biocare) in 285 arches. The sample was divided into two subgroups: 108 edentulous patients and 158 partially edentulous patients. Information was collected for each individual regarding expected remaining lifetime at the time of implant surgery. Cumulative survival rate (CSR) was calculated and compared for the two subgroups covering 10 years and was also compared to expected CSR data for normal populations of comparable distribution.Mortality was significantly decreased (P < .05) for partially edentulous compared with edentulous patients (-10.4%) after 10 years of follow-up. CSR for the elderly groups showed a significant decrease in mortality compared with comparable groups of normal populations (P < .05). There was no significant difference in morality between healthy/nonhealthy patients at first surgery or patients with reported/unreported implant failures (P > .05).Elderly partially edentulous patients had significantly lower mortality compared with edentulous patients over a 10-year period of follow-up. Both subgroups also showed significantly lower mortality compared with normal populations of comparable sex and age at the time of implant surgery. The observation is interpreted as that these patients are healthier and more motivated to replace their lost teeth with implants than the normal population rather than that implant treatment per se reduces mortality.
  •  
47.
  • Lundgren, T, et al. (författare)
  • Parathyroid hormone (1-34) receptor-binding and second-messenger response in rat incisor odontoblasts.
  • 1998
  • Ingår i: Calcified tissue international. - 0171-967X. ; 62:3, s. 255-9
  • Tidskriftsartikel (refereegranskat)abstract
    • Even though indirect evidence indicates that PTH exerts an anabolic effect on dentinogenesis, the existence of PTH receptors and any second-messenger response in odontoblasts have not been demonstrated. The aim of this study was to investigate whether rat incisor odontoblasts express PTH receptors, and to identify which second messenger pathway the hormone may activate. Odontoblasts were dissected from rat incisors. Amino-terminal (1-34) fragment rat PTH [rPTH(1-34)] conjugated to fluorescein isothiocyanate visualized receptor sites on the cell surface. Upon incubation of odontoblasts with rPTH(1-34), cAMP formation was increased. However, no fluctuations in intracellular calcium activity were observed upon rPTH(1-34) stimulation when using Fura-2 as a Ca2+ probe. In long-time incubations, stimulation with PTH(1-34) upregulated APase activity. The results demonstrate that rPTH(1-34) evokes an anabolic response in dentinogenically active odontoblasts, and that this may be mediated through the protein kinase A/cAMP pathway, whereas no indications for Ca2+ as a second messenger were evident.
  •  
48.
  • Meirelles, Luiz, 1974, et al. (författare)
  • Bone reaction to nano hydroxyapatite modified titanium implants placed in a gap-healing model
  • 2008
  • Ingår i: Journal Biomedical MAterials Research - A. - : Wiley. - 1549-3296 .- 1552-4965. ; 87:3, s. 624-631
  • Tidskriftsartikel (refereegranskat)abstract
    • Nanohydroxyapatite materials show similar chemistry to the bone apatite and depending on the underlying topography and the method of preparation, the nanohydroxyapatite may simulate the specific arrangement of the crystals in bone. Hydroxyapatite (HA) and other CaP materials have been indicated in cases in which the optimal surgical fit is not achievable during surgery, and the HA surface properties may enhance bone filling of the defect area. In this study, very smooth electropolished titanium implants were used as substrata for nano-HA surface modification and as control. One of each implant (control and nano HA) was placed in the rabbit tibia in a surgical site 0.7 mm wider than the implant diameter, resulting in a gap of 0.35 mm on each implant side. Implant stability was ensured by a fixating plate fastened with two side screws. Topographical evaluation performed with an optical interferometer revealed the absence of microstructures on both implants and higher resolution evaluation with AFM showed similar nanoroughness parameters. Surface pores detected on the AFM measurements had similar diameter, depth, and surface porosity (%). Histological evaluation demonstrated similar bone formation for the nano HA and electropolished implants after 4 weeks of healing. These results do not support that nano-HA chemistry and nanotopography will enhance bone formation when placed in a gap-healing model. The very smooth surface may have prevented optimal activity of the material and future studies may evaluate the synergic effects of the surface chemistry, micro, and nanotopography, establishing the optimal parameters for each of them.
  •  
49.
  • Nilsson, Andree, et al. (författare)
  • Infraposition of anterior maxillary implant-supported single-tooth restorations in adolescent and adult patients-A prospective follow-up study up to 6 years
  • 2019
  • Ingår i: Clinical Implant Dentistry and Related Research. - : John Wiley & Sons. - 1523-0899 .- 1708-8208. ; 21:5, s. 953-959
  • Tidskriftsartikel (refereegranskat)abstract
    • Background In the maxillary incisor area infraposition of implant restorations can be an esthetic problem. Purpose The aim was to analyze the prevalence of infraposition of single-tooth implant restorations in the anterior maxilla in adolescent and adult patients. Material and Methods The study comprised of 31 patients, 18 women and 13 men, with 39 restorations and with a mean and median age of 23.8 and 18.8 years, range 17.8 to 52.8 years, at the time of implant crown connection. The mean and median time in function for the restorations was 4.5 and 4.3 years respectively with a range of 3.3 to 6.6 years. Results Twenty restorations 51%, showed no signs of infraposition. A slight infraposition (<0.5 mm) was seen in 36% of the restorations. Only in one patient, the observed infraposition of the implant crown was more than 1 mm. We found no significant difference of the observed level of vertical infraposition, Score A (0 mm) and Score B (<0.5 mm), in subjects where the restoration was placed before the age of 20 years compared to the older patients. There were no significant differences in changes of the vertical infraposition when comparing different parameters such as age, gender, jaw relation (Angle-classes I-III), overbite/overjet, occlusal contact on the implant crown, bone augmentation before or at implant installation or if orthodontic treatment of the neighboring teeth had been made before or after the implant installation. Conclusions In the present study, there was a significant yet low correlation between the observed vertical infraposition of the single-tooth implant restoration and the subject's evaluation of the esthetics of the restoration (VAS). Fifty-one percent of the implant-supported crowns, showed no signs of vertical infraposition. A slight infraposition (< 0.5 mm) was however seen in 36% of the restorations. Only one crown showed a vertical infraposition of more than 1 mm.
  •  
50.
  • Nilsson, Sheida, et al. (författare)
  • A retrospective clinical study of fixed tooth- and implant-supported prostheses in titanium and cobalt-chromium-ceramic: 5-9-year follow-up
  • 2022
  • Ingår i: Clinical Oral Investigations. - : Springer Science and Business Media LLC. - 1432-6981 .- 1436-3771. ; 26:10, s. 6097-6103
  • Tidskriftsartikel (refereegranskat)abstract
    • Objectives The aim of this retrospective study was to evaluate the clinical outcome of fixed tooth- and implant-supported protheses manufactured in porcelain veneered cobalt-chromium (CoCr) or titanium with a follow-up period of 5-9 years. Materials and methods This study included 63 patients with a total of 86 fixed dental protheses (FDPs) (53 implant-supported and 33 tooth-supported). In total, 67 were short-span FDPs (3-5 units) and 19 were long-span FDPs (6-12 units). The FDPs were evaluated using a modified version of the California Dental Association (CDA). Results The binary regression analysis indicated that neither CoCr nor titanium had a statistically significant effect on the odds of success or survival of either tooth- or implant-supported FDPs. However, the success of FDPs was negatively affected by greater FDP length and general tooth wear. The survival of FDPs was negatively affected by increased FDP longevity. Conclusions This study found no statistically significant effect on the odds of success and survival outcomes for any combination of tooth-supported, implant-supported, porcelain-veneered CoCr, or porcelain-veneered titanium FDPs. As the number of FDPs was limited, the results should be interpreted with caution.
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