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  • 1. Ballerini, L.
    et al.
    Bocchi, L.
    Johansson, Carina B.
    Örebro University, Department of Health Sciences.
    Image segmentation by a genetic fuzzy c-means algorithm using color and spatial information2004Conference paper (Refereed)
  • 2. Ballerini, L.
    et al.
    Bocchi, L.
    Johansson, Carina B.
    Örebro University, Department of Health Sciences.
    Image segmentation by a genetic fuzzy c-means algorithm using color and spatial information2004Conference paper (Other academic)
  • 3. Ballerini, L
    et al.
    Franke-Stenport, V
    Johansson, Carina B
    Örebro University, Department of Health Sciences. Örebro University, Department of Clinical Medicine.
    Hoffman, M
    Boregfors, G
    Quantification of Bone Tissue Integration: a Comparative Study of Histomorphometrical Data2006In: European Society for Biomaterials, Nantes, France, Sept, 2006, 2006Conference paper (Refereed)
  • 4. Ballerini, Lucia
    et al.
    Franke-Stenport, Victoria
    Borgefors, Gunilla
    Johansson, Carina B.
    Örebro University, Department of Clinical Medicine.
    Comparison of histomorphometrical data obtained with two different image analysis methods2007In: Journal of materials science. Materials in medicine, ISSN 0957-4530, E-ISSN 1573-4838, Vol. 18, no 8, p. 1471-1479Article in journal (Refereed)
    Abstract [en]

    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.

  • 5. Bolind, P.
    et al.
    Johansson, Carina B.
    Örebro University, Department of Clinical Medicine.
    Balshi, T.
    Langer, B.
    Albrektsson, T.
    A study of 275 retrieved Brånemark oral implants2005In: The international journal of periodontics & restorative dentistry, ISSN 0198-7569, E-ISSN 1945-3388, Vol. 25, no 5, p. 425-437Article in journal (Refereed)
    Abstract [en]

    The aim of this report was to describe the bone tissue response to Branemark oral implants retrieved from patients. The material consisted of consecutively received Branemark threaded oral implants and related patient data provided by clinicians. The implant samples were processed into undecalcified sections for evaluation under the light microscope. The analysis demonstrated a lower percentage of bone-to-implant contact for the unloaded implants as compared to the loaded implants. When the threads were divided into four different regions, the loaded implants had a lower percentage of bone-contacting length at the thread top as compared to the other three regions.

  • 6. Bolind, P.
    et al.
    Johansson, Carina B.
    Örebro University, Department of Clinical Medicine.
    Johansson, P.
    van Steenberghe, D.
    Albrektsson, T.
    Histologic evaluation of Brånemark clinic oral implants retrieved from grafted sites2006In: Clinical Implant Dentistry and Related Research, ISSN 1523-0899, E-ISSN 1708-8208, Vol. 8, no 1, p. 44-53Article in journal (Refereed)
    Abstract [en]

    PURPOSE: The aim of this report is to quantitatively and qualitatively describe the bone tissue response to Brånemark implants retrieved from grafted sites in patients. MATERIALS AND METHOD: The material consists of consecutively received Brånemark implants retrieved from grafted sites. Thirty-five of these implants, retrieved from 16 patients, were suitable for the histologic evaluation of undecalcified sections in the light microscope. RESULTS: The unloaded implants were mainly lined with soft tissue, and sparse bone-implant contact was observed only in some sections. The loaded implants, with the exception of one implant removed due to mobility, had mature and new bone-implant contact. Resorption of graft through cutting cone structures was detected. Cement lines were found separating bone-like tissue albeit no cellular content and bone tissue with detectable osteocytes. CONCLUSION: In this heterogeneous group of implants from grafted sites, the unloaded implants showed limited bone-implant contact. The autografts showed seemingly mixed viability as judged by the cell content in the osteocyte lacunae and cement lines separating areas with filled and empty lacunae.

  • 7. Bolind, Pia
    et al.
    Johansson, Carina B.
    Örebro University, Department of Health Sciences.
    Becker, William
    Langer, Laureen
    Sevetz, Edward
    Albrektsson, Tomas O.
    A descriptive study on retrieved non-threaded and threaded implant designs2005In: Clinical Oral Implants Research, ISSN 0905-7161, E-ISSN 1600-0501, Vol. 16, no 4, p. 447-455Article in journal (Refereed)
    Abstract [en]

    OBJECTIVES:

    In the light microscope compare the amount of bone saucerization for non-threaded cylindrical and threaded implant designs in retrieved samples from patients.

    MATERIAL AND METHOD:

    Consecutively received retrieved oral implants from 117 patients, whereof 85 non-threaded cylindrical and 85 Brånemark implants, have been included in the study. For 75 non-threaded cylindrical and 46 Brånemark implants was the entire implant length available for calculation. Undecalcified ground sections were investigated in the light microscope with calculation of percentage of implant length coronal to the first bone-implant contact and percentage of bone to implant contact.

    RESULTS:

    Mean value for implant length coronal to first bone-implant contact was 65%, standard error of the mean (SEM) 3 (range 0-100%), for non-threaded cylindrical implants and 43%, SEM 6 (range 0-100%) for Brånemark implants. Mean values of bone contact along the entire implant length was 23%, SEM 2 (range 0-65%), for the non-threaded cylindrical implants and 33%, SEM 5 (range 0-93%) for the Brånemark implants.

    CONCLUSION:

    Within the limitations of this retrospective, retrieval study non-threaded cylindrical implants demonstrated a greater bone saucerization when evaluated in the light microscope.

  • 8. Bolind, Pia
    et al.
    Johansson, Carina B.
    Örebro University, Department of Clinical Medicine.
    Johansson, Petra
    Granström, Gösta
    Albrektsson, Tomas
    Retrieved implants from irradiated sites in humans: A histologic/histomorhpometric investigation of oral and craniofacial implants2006In: Clinical Implant Dentistry and Related Research, ISSN 1523-0899, E-ISSN 1708-8208, Vol. 8, no 3, p. 142-150Article in journal (Refereed)
    Abstract [en]

    Purpose The aim of this report was to quantitatively and qualitatively evaluate the tissue response to bone-anchored implants retrieved from irradiated sites in patients.

    Materials and Methods The material consists of 23 consecutively received Brånemark® implants (Nobel Biocare AB, Göteborg, Sweden) placed in pre- or postoperatively irradiated sites. Twenty-two of the 23 implants were suitable for histologic evaluation of undecalcified sections in the light microscope.

    Results The oral implants with shorter time in situ demonstrated sparse bone to implant contact with mainly dense connective tissue in the interface. However, for implants with longer time in situ, high amounts of bone-implant contact and bone fill of threads were noted. The mean values of bone-implant contact and bone area within the thread were calculated to 40% (16–94) and 70% (13–96), respectively. The craniofacial implants, with the exception of two implants lined with a capsular formation, demonstrated mature and newly formed bone at the bone-implant interface. The mean value for bone-metal contact was calculated to 45 and 53% for two specimens. The mean value for bone area within the thread ranged from 65 to 88% for three specimens.

    Conclusion The possibility to achieve bone anchorage of implants in irradiated tissue was supported by the findings in this study. However, due to limited material, conclusions with regard to radiation dose and bone tissue response to implants cannot be stated.

  • 9. Carlsson, C.
    et al.
    Johansson, Carina B.
    Örebro University, Department of Clinical Medicine.
    Holmgren Peterson, K.
    Sul, Y. T.
    Comparisons of bone tissue formation around pure titanium implants using light- and fluorescence microscopically techniques2006Conference paper (Refereed)
  • 10.
    Carlsson, Carolina
    et al.
    Örebro University, School of Health and Medical Sciences.
    Holmgren-Peterson, Kajsa
    Jönsson, Jörgen
    Johansson-Hammarström, Petra
    Albrektsson, Ann
    Hoffman, Maria
    Sul, Young-Taeg
    Johansson, Carina B.
    Örebro University, School of Health and Medical Sciences.
    Comparing light and fluorescence microscopic data: A pilot study of titanium and magnesium oxide implant integration in rabbit bone2009In: Titanium: The International Journal of Dental Implants & Biomaterials, ISSN 1946-0155, Vol. 1, no 1, p. 61-70Article in journal (Refereed)
  • 11. Ellingsen, Jan Eirik
    et al.
    Johansson, Carina B.
    Örebro University, Department of Clinical Medicine.
    Wennerberg, Ann
    Holmén, Anders
    Improved Retention and Bone-to-Implant Contact with Fluoride-Modified Titanium Implants2004In: International Journal of Oral & Maxillofacial Implants, ISSN 0882-2786, E-ISSN 1942-4434, Vol. 19, no 5, p. 659-666Article in journal (Refereed)
    Abstract [en]

    Purpose: The purpose of the present study was to investigate whether a fluoride modification of the titanium surface would have an effect on bone response after implantation. Materials and Methods: Titanium-oxide–blasted titanium implants with and without fluoride modification were investigated in a rabbit tibia model. Quantitative analysis of surface roughness, biomechanical interlocking, and in vivo tissue reactions in rabbit bone at 1 and 3 months after placement were compared. Results: The fluoride-modified test implants had a slightly smoother surface (Sa: 0.91 ± 0.14 µm) than the unmodified control implants (Sa: 1.12 ± 0.24 µm). Significantly higher removal torque values (85 ± 16 Ncm vs 54 ± 12 Ncm) and shear strength between bone and implants (23 ± 9 N/mm2 vs 15 ± 5 N/mm2) were measured for the fluoride-modified implants after 3 months. The histomorphometric evaluations demonstrated higher bone-to-implant contact for test implants at 1 month (35% ± 14% vs 26% ± 8%) and 3 months (39% ± 11% vs 31% ± 6%) after placement. Discussion: Implant surface modification with fluoride may result in morphologic and physiochemical phenomena that are of significance for the bone response. Another possible explanation for the findings in the present study is that a surface modification changes the surface chemical structures to be more suitable for bone bonding. Conclusion: Based on the biomechanical and histomorphometric data, the fluoride-modified titanium implants demonstrated a firmer bone anchorage than the unmodified titanium implants. These implants achieved greater bone integration than unmodified titanium implants after a shorter healing time. (More than 50 references.)

  • 12. Franke Stenport, V
    et al.
    Johansson, Carina B
    Örebro University, Department of Health Sciences.
    Evaluations of Bone Tissue Integration to Pure and Alloyed Titanium Implants2008In: Clinical Implant Dentistry and Related Research, ISSN 1523-0899, E-ISSN 1708-8208, Vol. 10, no 3, p. 191-199Article in journal (Refereed)
    Abstract [en]

    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.

  • 13. Franke Stenport, Victoria
    et al.
    Johansson, Carina B.
    Örebro University, Department of Clinical Medicine.
    Enamel matrix derivative and titanium implants: An experimental pilot study in the rabbit2003In: Journal of Clinical Periodontology, ISSN 0303-6979, E-ISSN 1600-051X, Vol. 30, no 4, p. 359-363Article in journal (Refereed)
    Abstract [en]

    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.

  • 14. Franke Stenport, Victoria
    et al.
    Johansson, Carina B.
    Örebro University, Department of Health Sciences. Örebro University, Department of Clinical Medicine.
    Sawase, Takashi
    Yamasaki, Yasuharu
    Oida, Shinichiro
    FGF-4 and titanium implants: a pilot study in rabbit bone2003In: Clinical Oral Implants Research, ISSN 0905-7161, E-ISSN 1600-0501, Vol. 14, no 3, p. 363-368Article in journal (Refereed)
    Abstract [en]

    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 μg 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.

  • 15. Franke-Stenport, V.
    et al.
    Johansson, Carina B.
    Örebro University, Department of Clinical Medicine.
    Commercially pure titanium and titanium alloy implants in bone in vivo study after 16weeks2005Conference paper (Refereed)
  • 16. Franke-Stenport, Victoria
    et al.
    Johansson, Carina B.
    Örebro University, Department of Health Sciences. Örebro University, Department of Clinical Medicine.
    Joo Heo, S.
    Aspenberg, P.
    Albrektsson, T.
    Titanium implants and BMP-7 in bone: an experimental model in the rabbit2003In: Journal of materials science. Materials in medicine, ISSN 0957-4530, E-ISSN 1573-4838, Vol. 14, no 3, p. 247-254Article in journal (Refereed)
    Abstract [en]

    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.

  • 17. Ivanoff, Carl-Johan
    et al.
    Widmark, Göran
    Johansson, Carina B.
    Örebro University, Department of Health Sciences. Örebro University, Department of Clinical Medicine.
    Wennerberg, Ann
    Histologic evaluation of bone response to oxidized and turned titanium micro-implants in human jawbone2003In: International Journal of Oral & Maxillofacial Implants, ISSN 0882-2786, E-ISSN 1942-4434, Vol. 18, no 3, p. 341-348Article in journal (Refereed)
    Abstract [en]

    PURPOSE:

    To evaluate the human bone tissue response to 2 surfaces (oxidized or turned) on commercially available titanium implants.

    MATERIALS AND METHODS:

    Screw-type turned (control) and oxidized (test) micro-implants were manufactured in the same manner as commercially available turned and oxidized (TiUnite, Brånemark System) implants. The thickness of the oxide layer of the test implants was on average 10 microm, corresponding to the oxide thickness of the apical part of the TiUnite implant. Twenty patients received 1 test and 1 control micro-implant each during implant surgery. Before placement, the surface topography of the implants was characterized with an optical confocal laser profilometer. After a mean healing period of 6.6 months in the maxilla and 3.5 months in the mandible, the micro-implants and surrounding tissue were removed with a trephine bur. Histologic sections were produced, and the specimens were analyzed histomorphometrically.

    RESULTS:

    Surface roughness and enlargement were greater for the oxidized implants than for the turned implants. All micro-implants, except for 2 controls, were found to be clinically stable at the time of retrieval. Histomorphometric evaluation demonstrated significantly higher bone-to-implant contact for the oxidized implants, whether placed in the maxilla or in the mandible. Significantly more bone was found inside the threaded area for the oxidized implants placed in the mandible and maxilla, but there was no difference between implants with regard to position (maxilla or mandible).

    DISCUSSION:

    The stronger bone response to the oxidized implants may have contributed to the fact that 2 control implants but no test implants were lost. The reason for these findings may depend on one or multiple differences of the surfaces between test and control implants: (1) the thicker oxide layer itself, (2) increased surface roughness, (3) different surface morphology in terms of porosity, or (4) change in crystal structure.

    CONCLUSION:

    The present histologic study in human jawbone demonstrated a significantly higher bone response for anodic oxidized titanium implants than for implants with a turned surface.

  • 18. Jimbo, Ryo
    et al.
    Ivarsson, Mikael
    Örebro University, School of Health and Medical Sciences.
    Koskela, Anita
    Örebro University, School of Health and Medical Sciences.
    Sul, Young-Taeg
    Johansson, Carina B.
    Örebro University, School of Health and Medical Sciences.
    Protein adsorption to surface chemistry and crystal structure modification of titanium surfaces2010In: Journal of oral & maxillofacial research, ISSN 2029-283X, Vol. 1, no 3, p. e3-Article in journal (Refereed)
    Abstract [en]

    Objectives: To observe the early adsorption of extracellular matrix and blood plasma proteins to magnesium-incorporated titanium oxide surfaces, which has shown superior bone response in animal models.

    Material and Methods: Commercially pure titanium discs were blasted with titanium dioxide (TiO2) particles (control), and for the test group, TiO2 blasted discs were further processed with a micro-arc oxidation method (test). Surface morphology was investigated by scanning electron microscopy, surface topography by optic interferometry, characterization by X-ray photoelectron spectroscopy (XPS), and by X-ray diffraction (XRD) analysis. The adsorption of 3 different proteins (fibronectin, albumin, and collagen type I) was investigated by an immunoblotting technique.

    Results: The test surface showed a porous structure, whereas the control surface showed a typical TiO2 blasted structure. XPS data revealed magnesium-incorporation to the anodic oxide film of the surface. There was no difference in surface roughness between the control and test surfaces. For the protein adsorption test, the amount of albumin was significantly higher on the control surface whereas the amount of fibronectin was significantly higher on the test surface. Although there was no significant difference, the test surface had a tendency to adsorb more collagen type I.

    Conclusions: The magnesium-incorporated anodized surface showed significantly higher fibronectin adsorption and lower albumin adsorption than the blasted surface. These results may be one of the reasons for the excellent bone response previously observed in animal studies.

  • 19.
    Jimbo, Ryo
    et al.
    Department of Prosthodontics, Faculty of Odontology, Malmö, University, Malmö, Sweden; Department of Biomaterials, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.
    Sotres, Javier
    Department of Biomedical Laboratory Science and Technology, Faculty of Health and Society, Malmö University, Malmö, Sweden.
    Johansson, Carina
    Örebro University, School of Health and Medical Sciences, Örebro University, Sweden. Department of Clinical Medicine, Faculty of Health and Medical Sciences, Örebro University, Örebro, Sweden.
    Breding, Karin
    Promimic AB, Göteborg, Sweden.
    Currie, Fredrik
    Promimic AB, Göteborg, Sweden.
    Wennerberg, Ann
    Department of Prosthodontics, Faculty of Odontology, Malmö, University, Malmö, Sweden; Department of Biomaterials, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.
    The biological response to three different nanostructures applied on smooth implant surfaces2012In: Clinical Oral Implants Research, ISSN 0905-7161, E-ISSN 1600-0501, Vol. 23, no 6, p. 706-712Article in journal (Refereed)
    Abstract [en]

    Objective: To evaluate the biological effects of three calcium phosphate (CaP) coatings with nanostructures on relatively smooth implant surfaces.

    Material and methods: Stable CaP nanoparticle suspensions of different particle sizes and structures were coated onto implants by immersion and subsequent heat treatment. An uncoated implant was used as the control. After topographical and chemical characterizations, implants were randomly inserted into rabbit tibiae for removal torque (RTQ) testing. To confirm the biological reaction, implants were placed in the bilateral femurs of three rabbits.

    Results: The topographical characterization showed that each surface had different nanostructural characteristics and X-ray photon spectroscopy showed various CaP compositions. The control and test groups had different nanotopographies; however, the differences among the test groups were only significant for Surfaces B and C and the rest were insignificant. The RTQ tests showed significantly higher values in two test groups (Surface A and Surface C). Histologically, no adverse effects were seen in any group. Histomorphometrical evaluation showed comparable or better osseointegration along the implant threads in the test groups.

    Conclusion: The three different CaP coatings with nanostructures on the implant surfaces had enhancing effects on osseointegration. Along with the surface nanotopography, the CaP chemistry might have influenced the biological outcomes.

  • 20.
    Johansson, Carina B.
    et al.
    Örebro University, School of Health and Medical Sciences.
    Adell, Ragnar
    Örebro University, School of Health and Medical Sciences.
    Gottlow, J.
    Sul, Y.-T.
    Nannmark, U.
    Osseointegration yesterday, today and tomorrow2009Conference paper (Refereed)
  • 21.
    Johansson, Carina B.
    et al.
    Örebro University, School of Health and Medical Sciences.
    Jimbo, Ryo
    Department of Biomaterials, Institute of Clinical Sciences, Sahlgrenska Academy and Department of Prosthodontics, Faculty of Odontology, Malmö University, Malmö, Sweden; Gothenburg University, Gothenburg, Sweden.
    Stefenson, Per
    School of Health and Medical Sciences, Department of Clinical Medicine, Örebro University, Örebro, Sweden.
    Ex vivo and in vivo biomechanical test of implant attachment to various materials: introduction of a new user-friendly removal torque equipment2012In: Clinical Implant Dentistry and Related Research, ISSN 1523-0899, E-ISSN 1708-8208, Vol. 14, no 4, p. 603-611Article in journal (Refereed)
    Abstract [en]

    Objective:The removal torque (RTQ) analysis is commonly used for biomechanical evaluation of osseointegration. The overall aim of this study was to verify results obtained with a newly developed equipment for biomechanical testing of osseointegration.

    Methods: Verification of the new equipment for biomechanical tests involved three experiments: Part I, comparison of RTQ between implants placed in four different types of dental synthetic plasters. Part II, comparison of RTQ between custom made, experimentally used implants to self-tapping, commercially available implants molded in the same type of dental plaster. Part III, comparison of RTQ between commercially pure titanium implants to Ti6Al4V implants placed in rabbit bone, 6 weeks after insertion. Briefly, for all experiments, the peak RTQ values and the removal process were recorded every 0.01 seconds up to 10 seconds. After the measurements, peak RTQ values were converted to shear strength.

    Results: The developed equipment sensitively responded to the changes of properties related to the molding plasters, implant topographies, and materials. The monitored graphs corresponded well to the expected properties of the different implants and tested materials.

    Conclusion: The new RTQ equipment proved to be accurate and could add new knowledge in understanding the biomechanical aspects of osseointegration.

  • 22.
    Johansson, Carina B.
    et al.
    Örebro University, Department of Clinical Medicine.
    Lindblad, J.
    Sarve, H.
    Bernhardt, R.
    Beckmann, F.
    Herzen, J.
    Borgefors, G.
    Scharnweber, D.
    Improving the knowledge of integration of medical devices in bone: a comparison of 3D STμCT data to histomorphometrical data obtained on cut and ground sections2007Report (Other (popular science, discussion, etc.))
  • 23.
    Johansson, Carina B.
    et al.
    Örebro University, School of Health and Medical Sciences.
    Sarve, H.
    Lindblad, J.
    Borgefors, G.
    Bernhardt, R.
    Beckmann, F.
    State of the art techniques may not be “simple as that” to implement in biomaterials research2009Conference paper (Refereed)
  • 24.
    Johansson, Carina B.
    et al.
    Örebro University, Department of Clinical Medicine.
    Sul, Y. T.
    Albrektsson, T.
    Biochemical bonding of biomaterial2005Conference paper (Refereed)
  • 25.
    Johansson, Carina B.
    et al.
    Örebro University, Department of Health Sciences.
    Wennerberg, A.
    Boström-Junemo, K.
    Holmen, A.
    Hansson, S.
    In vivo comparisons of TiO2 blasted and fluoride modified implants in rabbit bone2004Conference paper (Refereed)
  • 26. Johansson, P.
    et al.
    Johansson, Carina B.
    Örebro University, Department of Clinical Medicine.
    Does tissue fixation and sample thickness matter in bone-biology research?2005Conference paper (Refereed)
  • 27.
    Kang, Byung-Soo
    et al.
    Department of Biomaterials/Handicap Research, Institute for Clinical Sciences, The Sahlgrenska Academy at University of Gothenburg, Gothenburg, Sweden.
    Sul, Young-Taeg
    Department of Biomaterials/Handicap Research, Institute for Clinical Sciences, The Sahlgrenska Academy at University of Gothenburg, Gothenburg, Sweden; Institute for Clinical Dental Research, Korea University, Seoul, South Korea.
    Johansson, Carina B.
    Örebro University, School of Health and Medical Sciences, Örebro University, Sweden. Department of Clinical Medicine, School of Health and Medical Sciences, Örebro University, Sweden.
    Oh, Se-Jung
    Department of Physics and Astronomy, Seoul National University, Seoul, South Korea .
    Lee, Hyun-Ju
    National Center for Inter-University Research Facility, Seoul National University, Seoul, South Korea.
    Albrektsson, Tomas
    Department of Biomaterials/Handicap Research, Institute for Clinical Sciences, The Sahlgrenska Academy at University of Gothenburg, Gothenburg, Sweden.
    The effect of calcium ion concentration on the bone response to oxidized titanium implants2012In: Clinical Oral Implants Research, ISSN 0905-7161, E-ISSN 1600-0501, Vol. 23, no 6, p. 690-697Article in journal (Refereed)
    Abstract [en]

    Aim: To investigate the effect of calcium concentration on the bone tissue response to Ca-incorporated titanium implants.

    Materials and methods: Two titanium surfaces containing 4.2% and 6.6% calcium were prepared using the micro-arc oxidation process. The implants were inserted in the tibia of nine New Zealand White rabbits. After 6 weeks of healing, the bone response to the implants was quantitatively compared by biomechanical and histomorphometrical measurements.

    Results: Ca 4.2% and Ca 6.6% containing implants revealed no distinctive differences in their qualitative surface chemistry; chemical bonding state of Ca in titanium oxide was mainly calcium titanates. No significant differences were observed between two implants in peak removal torque and shear strength comparisons (P>0.05). Histomorphometrical analyses presented no significant differences in bonemetal contact, bone area and newly formed bone measurements between two implants (P>0.05).

    Conclusions: From biomechanical and histomorphometrical measurements, the two calcium concentrations in this study did not differ significantly with respect to their influence on the bone tissue response. This similar bone response in rabbit tibiae may be explained by the similarity of the qualitative Ca chemistry in titanium surfaces.

  • 28. Koskela, Anita
    et al.
    Ivarsson, M.
    Sul, Y. T.
    Johansson, Carina B.
    Örebro University, Department of Clinical Medicine.
    Svensson, B.
    In vivo and in vitro tests of adhesion to biomaterials2007Conference paper (Refereed)
  • 29. Lindblad, Joakim
    et al.
    Sladoje, Natasia
    Curic, Vladimir
    Sarve, Hamid
    Johansson, Carina B.
    Örebro University, School of Health and Medical Sciences.
    Borgefors, Gunilla
    Improved quantification of bone remodelling by utilizing fuzzy based segmentation2009In: Image analysis / [ed] Arnt-Børre Salberg, Jon Yngve Hardeberg, Robert Jenssen, Berlin: Springer, 2009, p. 750-759Conference paper (Refereed)
    Abstract [en]

    We present a novel fuzzy theory based method for the segmentation of images required in histomorphometrical investigations of bone implant integration. The suggested method combines discriminant analysis classification controlled by an introduced uncertainty measure, and fuzzy connectedness segmentation method, so that the former is used for automatic seeding of the later. A thorough evaluation of the proposed segmentation method is performed. Comparison with previously published automatically obtained measurements, as well as with manually obtained ones, is presented. The proposed method improves the segmentation and, consequently, the accuracy of the automatic measurements, while keeping advantages with respect to the manual ones, by being fast, repeatable, and objective.

  • 30. Mordenfeld, A.
    et al.
    Hallman, M.
    Johansson, Carina B.
    Örebro University, School of Health and Medical Sciences.
    Albrektsson, T.
    Histological analyses of biopsies harvested 11 years after maxillary sinus floor augmentation with an 80:20 mixture of deproteinized bovine and autogenous bone2009Conference paper (Refereed)
  • 31.
    Mordenfeld, Arne
    et al.
    Dept Oral & Maxillofacial Surg, Publ Hlth Serv, Gävle, Sweden; Ctr Res & Dev, Uppsala Univ, Gavleborg, Sweden; Dept Biomat, Inst Clin Sci, Univ Gothenburg, Gothenburg, Sweden.
    Hallman, Mats
    Dept Oral & Maxillofacial Surg, Publ Hlth Serv, Gävle, Sweden; Ctr Res & Dev, Uppsala Univ, Gävleborg, Sweden.
    Johansson, Carina B.
    Örebro University, School of Health and Medical Sciences.
    Albrektsson, Tomas
    Dept Biomat, Inst Clin Sci, Univ Gothenburg, Gothenburg, Sweden.
    Histological and histomorphometrical analyses of biopsies harvested 11 years after maxillary sinus floor augmentation with deproteinized bovine and autogenous bone2010In: Clinical Oral Implants Research, ISSN 0905-7161, E-ISSN 1600-0501, Vol. 21, no 9, p. 961-970Article in journal (Refereed)
    Abstract [en]

    Objective The purpose of the present study was to histologically and histomorphometrically evaluate the long-term tissue response to deproteinized bovine bone (DPBB) particles used in association with autogenous bone and to compare particle size after 6 months and 11 years, in the same patients, in order to determine possible resorption. Material and methods Twenty consecutive patients (14 women and six men) with a mean age of 62 years (range 48-69 years) with severe atrophy of the posterior maxilla were included in this study. Thirty maxillary sinuses with < 5 mm subantral alveolar bone were augmented with a mixture of 80% DPBB and 20% autogenous bone. Eleven years (mean 11.5 years) after augmentation, biopsies were taken from the grafted areas of the 11 patients who volunteered to participate in this new surgical intervention. The following histomorphometrical measurements were performed in these specimens: total bone area in percentage, total area of the DPBB, total area of marrow space, the degree of DPBB-bone contact (percentage of the total surface length for each particle), the length of all DPBB particles and the area of all DPBB particles. The length and the area of the particles were compared with samples harvested from the same patients at 6 months (nine samples) and pristine particles from the manufacturer. Results The biopsies consisted of 44.7 +/- 16.9% lamellar bone, 38 +/- 16.9% marrow space and 17.3 +/- 13.2% DPBB. The degree of DPBB to bone contact was 61.5 +/- 34%. There were no statistically significant differences between the length and area of the particles after 11 years compared with those measured after 6 months in the same patients or to pristine particles from the manufacturer. Conclusion DPBB particles were found to be well integrated in lamellar bone, after sinus floor augmentation in humans, showing no significant changes in particle size after 11 years.

  • 32.
    Nyberg, Jan
    et al.
    Örebro University, School of Health and Medical Sciences, Örebro University, Sweden. Örebro University hospital, Örebro, Sweden.
    Hertzman, Sven
    Sahlgrenska University Hospital, Gothenburg, Sweden.
    Svensson, Börje
    Örebro University Hospital, Örebro, Sweden.
    Johansson, Carina B.
    Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.
    Osseointegration of implants in irradiated bone with and without hyperbaric oxygen treatment: an experimental study in rat tibiae2013In: International Journal of Oral & Maxillofacial Implants, ISSN 0882-2786, E-ISSN 1942-4434, Vol. 28, no 3, p. 739-746Article in journal (Refereed)
    Abstract [en]

    Purpose: Hyperbaric oxygen (HBO) has been recommended to enhance implant osseointegration in irradiated bone. The aim of this study was to further investigate the effects of HBO on implant integration in irradiated bone tissue.

    Materials and Methods: The present study was an experimental intraindividual study in 16 rats. A single fraction of 20 Gy external irradiation was applied to one rat hind leg, while the other served as a nonirradiated control. Three days after radiation, two implants were inserted in each tibial tuberosity. The rats were divided into two groups: non-HBO treated (group 1) and HBO treated (group 2). Five weeks after radiation, removal torque tests were performed. Implants with surrounding tissue were processed to undecalcified cut and ground sections for histomorphometric evaluations of bone-to-implant contact and bone area. Retrieved bones were also investigated with dual-energy x-ray absorptiometry.

    Results: The non-HBO treated rats (group 1) demonstrated higher, but not statistically significantly higher, values in the nonirradiated leg for all investigated parameters compared to the HBO-treated rats (group 2). However, the mean value for bone area was significantly higher in the irradiated sides compared to the nonirradiated control sides.

    Conclusions: In the present study, HBO treatment did not have a significant impact on osseointegration of implants in irradiated bone.

  • 33.
    Nyberg, Jan
    et al.
    Örebro University, School of Health and Medical Sciences. Örebro University Hospital, Örebro, Sweden.
    Hertzman, Sven
    Sahlgrenska University Hospital, Göteborg, Sweden.
    Svensson, Börje
    Örebro University, School of Health and Medical Sciences. Örebro University Hospital, Örebro, Sweden.
    Johansson, Petra
    Sahlgrenska Academy, Institute of Clinical Sciences, University of Gothenburg, Göteborg, Sweden.
    Granström, Gösta
    Sahlgrenska Academy, Institute of Clinical Sciences, University of Gothenburg, Göteborg, Sweden.
    Johansson, Carina B.
    Örebro University, School of Health and Medical Sciences. Örebro University Hospital, Örebro, Sweden.
    Single-dose irradiation followed by implant insertion in rat bone: An investigative study to find a critical level for osseointegration2010In: Journal of Osseointegration, ISSN 2036-4121, Vol. 2, no 2, p. 52-60Article in journal (Refereed)
    Abstract [en]

    Aim: No general consensus exists regarding the ideal time to insert implants in bone after irradiation or how the various irradiation doses influence implant success. This study aims at investigating integration of implants in pre-irradiated rat bone and find a critical level doses that cause disturbed osseointegration.

    Materials and methods: Single irradiation doses of 2, 5, 10, 20 and 30 Gy were given to one leg of adult rats 3 days prior to insertion of screw-shaped implants whereas the other leg served as a non-irradiated control. The follow up was 5 weeks. Bone implant contact (BIC) and bone area (BA) were measured on undecalcified cut and ground sections in the light microscope. The tissue quality was also examined in the light microscope.

    Results: Doses of 5 and 10 Gy resulted in 25% higher contact values for the irradiated samples compared to non-irradiated controls. The most impaired integration occurred when doses of 20 Gy were given, revealing a 50% difference between the irradiated (25%) and the non irradiated samples (50%). The bone area demonstrated no major quantitative differences albeit the qualitative observations differed substantially being most pronounced in the 20 and 30 Gy irradiated samples.

    Conclusions: The osseointegration was substantially impaired after radiation doses of 20 and 30 Gy. Quantitative data alone are insufficient to describe implant integration in situation like this. Qualitative observations are of utmost importance and require great attention. The importance of judging and describing various grades of tissue damage is complicated but necessary. Based on the results obtained in this study, full scale experiments are now ongoing.

  • 34.
    Nyberg, Jan
    et al.
    Örebro University, School of Health and Medical Sciences.
    Hertzmann, S.
    Svensson, Börje
    Örebro University, School of Health and Medical Sciences.
    Johansson, Carina B.
    Örebro University, School of Health and Medical Sciences.
    Implant integration in irradiated bone2009Conference paper (Refereed)
  • 35.
    Nyberg, Jan
    et al.
    Örebro University, School of Health and Medical Sciences.
    Svensson, Börje
    Johansson, Carina B.
    Örebro University, School of Health and Medical Sciences.
    Implant integration in compromised bone beds: a pilot study in rat bone2008Conference paper (Refereed)
  • 36. Ramires, P. A.
    et al.
    Wennerberg, Ann
    Johansson, Carina B.
    Örebro University, Department of Health Sciences. Örebro University, Department of Clinical Medicine.
    Cosentino, F.
    Tundo, S.
    Milella, E.
    Biological behavior of sol-gel coated dental implants2003In: Journal of materials science. Materials in medicine, ISSN 0957-4530, E-ISSN 1573-4838, Vol. 14, no 6, p. 539-545Article in journal (Refereed)
    Abstract [en]

    The biocompatibility of dental implants coated with titania/hydroxyapatite (HA) and titania/bioactive glass (BG) composites obtained via sol-gel process was investigated using an in vitro and in vivo model. A device for the in vitro testing of screw-shaped dental implants was developed, in order to well compare the two experimental models studying the behavior of human MG63 osteoblast-like cells seeded onto a particular geometry. The expression of some biochemical parameters of osteoblastic phenotype (alkaline phosphatase specific activity, collagen and osteocalcin production) and some indications on cells morphology obtained by scanning electron microscopy were evaluated. The in vitro and in vivo models were compared after implants insertion in rabbit tibia and femur. The removal torque and histomorphometric parameters (percentage of bone in contact with implant surface and the amount of bone inside the threaded area) were examined. A good agreement was found between the in vitro and in vivo models. These experiments showed better performances of HA and BG sol-gel coated dental implants with respect to uncoated titanium; in particular, it was found that in vitro the HA coating stimulates osteoblastic cells in producing higher level of ALP and collagen, whereas in vivo this surface modification resulted in a higher removal torque and a larger bone-implant contact area. This behavior could be ascribed to the morphology and the chemical composition of the implants with rough and bioactive surfaces.

  • 37. Reigstad, O.
    et al.
    Franke-Stenport, V.
    Johansson, Carina B.
    Örebro University, Department of Clinical Medicine.
    Wennerberg, A.
    Rökkum, M.
    Reigstad, A.
    Improved bone ingrowth and fixation with a thin calcium phosphate coating intended for complete resorption2007In: Journal of biomedical materials research. Part B, Applied biomaterials, ISSN 1552-4973, Vol. 83B, no 1, p. 9-15Article in journal (Refereed)
    Abstract [en]

    Bonit is claimed to be a resorbable electrochemically deposited calcium phosphate coating consisting mainly of brushite, which is a hydroxyapatite precursor. This study involved a comparison of Ti6Al4V screw-shaped implants with and without a 15 +/- 5 microm Bonit coating in rabbit tibia and femur, after 6 and 12 weeks of insertion. The biomechanical removal torque test showed significantly increased values for the coated implants after 12 weeks (p < 0.05) but not after 6 weeks of integration. Higher bone-implant contact was found for the coated implants in the tibia after 6 weeks and for both tibial and femoral screws after 12 weeks (p < 0.05). There was no difference in the inflammatory reaction around the implants, and possible grains of the coating could be detected after 6 weeks, but not after 12 weeks of follow-up. This unloaded short-term study has shown promising results for the easily applicable and resorbable coat (Bonit) compared to uncoated titanium-alloy implants.

  • 38. Reigstad, O.
    et al.
    Johansson, Carina B.
    Örebro University, Department of Health Sciences.
    Wennerberg, A.
    Rökkum, M.
    Reigstad, A.
    Quantitative evaluation of Ti6Al4V implants with and without an electrochemically deposited CaP coating2004Conference paper (Refereed)
  • 39. Reigstad, Ole
    et al.
    Johansson, Carina B.
    Örebro University, School of Health and Medical Sciences.
    Stenport, Victoria
    Wennerberg, Ann
    Reigstad, Astor
    Rökkum, Magne
    Different patterns of bone fixation with hydroxyapatite and resorbable CaP coatings in the rabbit tibia at 6, 12, and 52 weeks2011In: Journal of Biomedical Materials Research. Part B - Applied biomaterials, ISSN 1552-4973, E-ISSN 1552-4981, Vol. 99B, no 1, p. 14-20Article in journal (Refereed)
    Abstract [en]

    Applying bioactive coatings on orthopedic implants can increase the fixation and long-term implant survival. In our study, we compared a resorbable electrochemically deposited calcium phosphate coating (Bonit (R)) to a thin (40 mu m) plasma-sprayed hydroxyapatite (HA) coating, applied on grit-blasted screw-shaped Ti-6Al-4V implants in the cortical region of rabbit tibia, implanted for 6, 12, and 52 weeks. The removal torque results demonstrated stronger bone-to-implant fixation for the HA than Bonit-coated screws at 6 and 12 weeks. After 52 weeks, the fixation was in favor of the Bonit-coated screws, but the difference was statistically insignificant. Coat flaking and delamination of the HA with multinucleated giant cell activity and bone resorption observed histologically seemed to preclude any significant increase in fixation comparing the HA implants at 6 versus 12 weeks and 12 versus 52 weeks. The Bonit-coated implants exhibited increasing fixation from 6 to 12 weeks and from 12 to 52 weeks, and the coat was resorbed within 6 weeks, with minimal activity of multinucleated giant cells or bone resorption. A different fixation pattern was observed for the two coatings with a sharper but time limited increase in fixation for the HA-coated screws, and a slower but more steadily increasing fixation pattern for the Bonit-coated screws. The side effects were more serious for the HA coating and limiting the expected increase in fixation with time. (C) 2011 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 99B: 14-20, 2011.

  • 40. Reikerås, Olav
    et al.
    Johansson, Carina B.
    Örebro University, Department of Health Sciences. Örebro University, Department of Clinical Medicine.
    Sundfeldt, Mikael
    icke ÖU.
    Bone Ingrowths to Press-Fit and Loose-Fit Implants: Comparisons between Titanium and Hydroxyapatite2006In: Journal of long-term effects of medical implants, ISSN 1050-6934, E-ISSN 1940-4379, Vol. 6, no 2, p. 157-164Article in journal (Refereed)
    Abstract [en]

    The aim of this study was to investigate whether the coating of titanium (Ti) implants with hydroxyapatite (HA) might create a better fixation when titanium implants are implanted into a gap. In each of 16 rats, the medullary cavity of both femurs was entered by an awl from the trochanteric area. With steel burrs it was successively reamed to a diameter of 1.5 mm. In a random manner the proximal part of the cavity in half of the bones was reamed once again to a diameter of 2.0 mm. Nails with a diameter of 1.5 mm and a length of 34 mm were then inserted into the medullary cavity of these bones with press fit at the distal half and a gap to the bone in the proximal half. In the remaining bones the whole medullary canal was reamed to a diameter of 2.0 mm, and nails with a diameter of 2.0 mm and a length of 34 mm were introduced. In all cases, either a pure Ti nail or a Ti nail entirely plasma sprayed with HA was used in a random manner. The surface roughness of the pure Ti was characterized by Ra 2.6 microm and Rt 22 microm. Ra of HA was 7.5 microm and Rt 52 microm. At sacrifice after 16 weeks, both femurs were dissected free from soft tissues and then immersed in fixative. A specimen slice of about 5 mm in thickness was prepared from the subtrochanteric region with a water-cooled band saw. Sample preparation for undecalcified tissue followed the internal guidelines at the laboratories of the Department of Biomaterials/Handicap Research. Generally, bone contact to the nails with HA coating was more predictable than was bone contact to the Ti nails. But due to rather large variations in bone contact between the samples, statistical analyses revealed non-significant differences between the 4 groups (p = 0.083). There were no significant differences between Ti and HA coated nails of 2.0 mm (p = 0.633), nor between Ti and HA coated nails of 1.5 mm (p = 0.924). The pooled values for the 2.0 mm nails showed significantly higher bone bonding contact than the pooled values of the 1.5 mm nails (p = 0.011). Our results, then, indicate that bone bonding contact to implants with a loose fit insertion is less predictable than in press fit insertion, and HA coating seemed to be more predictable than pure Ti. However, due to large variations between the samples, the differences did not reach significant levels.

  • 41. Reikerås, Olav
    et al.
    Johansson, Carina B.
    Örebro University, Department of Technology.
    Sundfeldt, Mikael
    Hydroxyapatite and carbon coatings for fixation of unloaded titanium implants2004In: Journal of long-term effects of medical implants, ISSN 1050-6934, E-ISSN 1940-4379, Vol. 14, no 6, p. 443-454Article in journal (Refereed)
    Abstract [en]

    The aim of this study was to investigate the interaction between bone and pure titanium, titanium coated with hydroxyapatite (HA), and titanium coated with carbon in a rat femur model.In 25 rats, the medullary cavity of both femurs was entered by an awl from the trochanteric area. With steel burrs it was successively reamed to a diameter of 2.0 mm. Nails with a diameter of 2.0 mm and with a length of 34 mm were inserted in a random manner; either a pure titanium nail, a titanium nail entirely plasma-sprayed with a 75−100—μm layer of HA or a titanium nail coated with 2−10-μm carbon. The surface roughness of the pure titanium was characterized by Ra 2.6 μm and Rt 22 μm. Ra of HA was 7.5 μm and Rt 52 μm, and of carbon Ra was 0.4 μm and Rt 4.0 μm. Twelve rats were randomized to a follow up of 8 weeks, and the remaining 13 rats were followed for 16 weeks. At sacrifice both femora were dissected free from soft tissues and then immersed in fixative. A specimen slice of about 5 mm thickness was prepared from the subtrochanteric region with a water-cooled band-saw. Sample preparation for un-decalcified tissue followed the internal guidelines at the laboratories of Biomaterials/Handicap Research. At 8 weeks the median bone bonding contact of the implants was 43% (range 0−74) in the titanium group, 39% (0−75) in the HA group, and 3% (0−59) in the carbon group. At 16 weeks the corresponding figures were 58% (0−78) in the titanium group, 51% (15−75) in the HA group, and 8% (0−79) in the carbon group. In conclusion, we found great variability in bone bonding contact. In general, carbon-coated nails had reduced bone bonding contact both at 8 and at 16 weeks as compared to pure titanium or titanium coated with hydroxyapatite.

  • 42. Reikerås, Olav
    et al.
    Johansson, Carina B.
    Örebro University, Department of Technology.
    Sundfeldt, Mikael
    Hydroxyapatite enhances long-term fixation of titanium implants2006In: Journal of long-term effects of medical implants, ISSN 1050-6934, E-ISSN 1940-4379, Vol. 6, no 2, p. 165-173Article in journal (Refereed)
    Abstract [en]

    The aim of this study was to evaluate osseous integration of hydroxyapatite coated titanium implants over time as compared to pure titanium. In 20 rats the medullary cavity of both femoral bones was entered by an awl from the trochanteric area. With steel burrs it was successively reamed to a diameter of 2.0 mm. Nails with a diameter of 2.0 mm and with a length of 34 mm were inserted into the medullary cavity; a pure titanium nail on the left side and a titanium nail entirely plasma-sprayed with hydroxyapatite (HA) on the right side. The surface roughness of the pure titanium was characterized by Ra 2.6 μm and Rt 22 μm, and HA had a roughness of Ra 7.5 (arithmetical mean roughness) μm and Rt (maximum profile height) 52 μm. The rats were randomized to a follow-up of 6 and 12 months, respectively. At sacrifice the femoral bones were dissected free from soft tissues. The bones were radiographed and then immersed in fixative. A specimen-slice of about 5 mm thickness was prepared from the region under the trochanter minor with a water cooled band-saw. Sample preparation for undecalcified tissue followed the internal guidelines at the laboratories of Biomaterials/Handicap Research. At 6 months the median bone bonding contact of the implants was 40% (range 0−92) in the titanium group and 34% (0−86) in the HA group. At 12 months the median bone bonding contact was 51% (0−97) in the titanium group and 86% (72−98) in the HA group. In conclusion, we found a significant (p = 0.001) increase in bone bonding contact from 6 to 12 months of the HA coated nails and significantly (p = 0.043) enhanced bone bonding contact in HA coated nails at 12 months as compared to pure titanium nails.

  • 43. Romanos, G.
    et al.
    Johansson, Carina B.
    Örebro University, Department of Clinical Medicine.
    Immediate Loading with Complete Implant-Supported Restorations in an Edentulous Heavy Smoker: histologic and histomorphometric analyses2005In: International Journal of Oral & Maxillofacial Implants, ISSN 0882-2786, E-ISSN 1942-4434, Vol. 20, no 2, p. 282-290Article in journal (Refereed)
    Abstract [en]

    The clinical case presented is that of an edentulous female patient, a heavy smoker, who received implant-supported complete restorations in the maxilla and mandible using the immediate loading concept according to the Ankylos implant system. The patient received 12 commercially pure titanium (grade 2) Ankylos implants, 6 in the maxilla and 6 in the mandible. The implants were loaded immediately after surgery with temporary acrylic resin prostheses fabricated chairside using a prefabricated customized splint. The definitive ceramometal restorations were seated 4 months after surgery. Clinical and radiologic evaluation at 7 months after implant placement indicated functional bone anchorage of all implants, despite the patient being a smoker and having poor bone quality. The patient died 7 months after implant placement because of lung cancer; however, there was no known disease at the time of implant placement. After her death, the implants with the surrounding tissues were removed en bloc and examined histologically and histomorphometrically using undecalcified cut and ground sections. All implants were osseointegrated to some extent and surrounded by lamellar bone. However, around the upper, nonthreaded parts of the implants, much of the bone had been resorbed. In this region, fibrous connective tissue was in close contact with the titanium surface. Epithelial proliferation with pocket formation could not be observed in any of the implants. The histomorphometric evaluation of bone-implant contact in threads demonstrated a mean of approximately 51% of the available surface and a mean bone volume of approximately 52%, with a tendency toward greater contact and volume around the implants in the maxilla. If the nonthreaded cylindric portions of the implants were included, mean bone-implant contact was 46% and mean bone volume was 47%.

  • 44.
    Romanos, George E.
    et al.
    Dept Odontostomatol Sci, Sch Dent, Univ G dAnnunzio, Chieti, Italy.
    Traini, Tonino
    Dept Odontostomatol Sci, Sch Dent, Univ G dAnnunzio, Chieti, Italy.
    Johansson, Carina B.
    Örebro University, School of Health and Medical Sciences.
    Piattelli, Adriano
    Dept Odontostomatol Sci, Sch Dent, Univ G dAnnunzio, Chieti, Italy.
    Biologic Width and Morphologic Characteristics of Soft Tissues Around Immediately Loaded Implants: Studies Performed on Human Autopsy Specimens2010In: Journal of Periodontology, ISSN 0022-3492, E-ISSN 1943-3670, Vol. 81, no 1, p. 70-78Article in journal (Refereed)
    Abstract [en]

    Background: Esthetics and the health of oral implants are based upon the soft tissue reaction and biologic width (BW).

    Methods: Twelve dental implants were placed in the maxilla and mandible of a patient who smoked. Permanent standard abutments and temporary restorations were immediately fixed in place during the surgery stage. The definitive restorations were placed 4 months after loading without removal of the original abutments. After 10 months, the patient died, and the implants were removed en block and processed for histology.

    Results: The BW in the maxilla was 6.5 ± 2.5 mm, whereas in the mandible, it was 4.8 ± 1.3 mm (P = 0.017). The sulcular epithelium (SE) in the maxilla was 2.7 ± 0.8 mm, whereas in the mandible, it was 1.7 ± 0.4 mm (P <0.001). The junctional epithelium (JE) in the maxilla was 1.3 ± 0.4 mm, whereas in the mandible, it was 1.5 ± 0.5 mm (P = 0.164). The connective tissue (CT) in the maxilla was 2.5 ± 1.3 mm, whereas in the mandible, it was 1.6 ± 0.4 mm (P = 0.006). In the maxillary bone, the BW, SE, and CT were significantly longer than in the mandible, whereas for the JE, no statistically significant difference was observed.

    Conclusion: The soft tissue organization around dental implants was different for upper and lower jawbones.

  • 45. Sabel, Nina
    et al.
    Johansson, Carina B.
    Örebro University, School of Health and Medical Sciences.
    Kühnisch, Jan
    Robertson, Agneta
    Steiniger, Frank
    Norén, Jörgen G.
    Klingberg, Gunilla
    Nietzsche, Sandor
    Neonatal lines in the enamel of primary teeth: A morphological and scanning electron microscopic investigation2008In: Archives of Oral Biology, ISSN 0003-9969, E-ISSN 1879-1506, Vol. 53, no 10, p. 954-963Article in journal (Refereed)
  • 46. Sandén, B.
    et al.
    Olerud, C.
    Petrén-Mallmin, M.
    Johansson, Carina B.
    Örebro University, Department of Technology.
    Larsson, C.
    The significance of radiolucent zones surrounding pedicle screws: definition of screw loosening in spinal instrumentation2004In: Journal of Bone and Joint Surgery, ISSN 0301-620X, E-ISSN 2044-5377, Vol. 86 B, no 3, p. 457-461Article in journal (Refereed)
    Abstract [en]

    We examined the radiographs from a prospective clinical study of fixation by pedicle screws and those from an experimental study in a sheep model. In the clinical study, instruments were removed from 21 patients after implantation for 11 to 16 months and the extraction torques of the screws were recorded. A structured protocol was used for the radiological examinations. In the experimental study, loaded pedicle screw instrumentations were implanted in the sheep for six or 12 weeks. After radiological examination the pull-out resistance and the histological characteristics were studied. In the clinical study, all screws with radiolucent zones had a significantly reduced mean extraction torque compared with screws without radiolucent zones (16 +/- 10 Ncm v 403 +/- 220 Ncm; p < 0.0001). In the experimental study the mean maximum pull-out resistance for the screws with radiolucent zones was significantly lower than for those with no radiolucency (243 +/- 156 N v2214 +/- 578 N; p = 0.0006) and the mean bone-to-screw contact was reduced for screws with zones compared with those without zones (8 +/- 9% v 55 +/- 29%; p = 0.0002). Our findings showed that all screws with radiolucent zones had low extraction torques or low pull-out resistance. A radiolucent zone is a good indicator of loosening of a pedicle screw.

  • 47. Sarve, H.
    et al.
    Johansson, Carina B.
    Örebro University, Department of Clinical Medicine.
    Lindblad, J.
    Quantitative estimation of bone growth in the proximity of implants2007Conference paper (Refereed)
  • 48. Sarve, H.
    et al.
    Lindblad, J.
    Borgefors, G.
    Johansson, Carina B.
    Örebro University, School of Health and Medical Sciences.
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