| 1. |
- Sarve, Hamid, 1981-, et al.
(författare)
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Quantification of Bone Remodeling in SRuCTImages of Implants
- 2009
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Ingår i: 16th Scandinavian Conference, SCIA 2009, Oslo, Norway, June 15-18, 2009. - Heidelberg : Springer Verlag. - 9783642022296 ; , s. 770-779, s. 770-779
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Konferensbidrag (refereegranskat)abstract
- For quantification of bone remodeling around implants, wecombine information obtained by two modalities: 2D histological sectionsimaged in light microscope and 3D synchrotron radiation-based computedmicrotomography, SRμCT. In this paper, we present a methodfor segmenting SRμCT volumes. The impact of shading artifact at theimplant interface is reduced by modeling the artifact. The segmentationis followed by quantitative analysis. To facilitate comparison with existingresults, the quantification is performed on a registered 2D slicefrom the volume, which corresponds to a histological section from thesame sample. The quantification involves measurements of bone areaand bone-implant contact percentages.We compare the results obtained by the proposed method on the SRμCTdata with manual measurements on the histological sections and discussthe advantages of including SRμCT data in the analysis.
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| 2. |
- Mordenfeld, Arne, et al.
(författare)
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Histological and histomorphometrical analyses of biopsies harvested 11 years after maxillary sinus floor augmentation with deproteinized bovine and autogenous bone
- 2010
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Ingår i: Clinical Oral Implants Research. - : Wiley. - 0905-7161 .- 1600-0501. ; 21:9, s. 961-970
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 3. |
- Sarve, Hamid, et al.
(författare)
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Extracting 3D information on bone remodeling in the proximity of titanium implants in SRμCT image volumes.
- 2011
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Ingår i: Computer methods and programs in biomedicine. - : Elsevier BV. - 1872-7565 .- 0169-2607. ; 102:1, s. 25-34
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Tidskriftsartikel (refereegranskat)abstract
- Bone-implant integration is measured in several ways. Traditionally and routinely, 2D histological sections of samples, containing bone and the biomaterial, are stained and analyzed using a light microscope. Such histological section provides detailed cellular information about the bone regeneration in the proximity of the implant. However, this information reflects the integration in only a very small fraction, a 10 μm thick slice, of the sample. In this study, we show that feature values quantified on 2D sections are highly dependent on the orientation and the placement of the section, suggesting that a 3D analysis of the whole sample is of importance for a more complete judgment of the bone structure in the proximity of the implant. We propose features describing the 3D data by extending the features traditionally used for 2D-analysis. We present a method for extracting these features from 3D image data and we measure them on five 3D SRμCT image volumes. We also simulate cuts through the image volume positioned at all possible section positions. These simulations show that the measurement variations due to the orientation of the section around the center line of the implant are about 30%.
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| 4. |
- Lindblad, Joakim, 1973-, et al.
(författare)
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Improved Quantification of Bone Remodelling by Utilizing Fuzzy Based Segmentation
- 2009
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Ingår i: Image Analysis. - Berlin : Springer Verlag. - 9783642022296 ; 5575, s. 750-759
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Konferensbidrag (refereegranskat)abstract
- 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.
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| 5. |
- Sarve, Hamid, et al.
(författare)
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Methods for visualization of bone tissue in the proximity of implants
- 2010
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Ingår i: Computer vision and graphics. - Berlin : Springer. - 9783642159060 ; 6375, s. 243-250
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Konferensbidrag (refereegranskat)abstract
- In this work we present two methods for visualization of SRμCT-scanned 3D volumes of screw-shaped bone implant samples: thread fly-through and 2D unfolding. The thread fly-through generates an animation by following the thread helix and extracting slices along it. Relevant features, such as bone ratio and bone implant contact, are computed for each slice of the animation and displayed as graphs beside the animation. The 2D unfolding, on the other hand, maps the implant surface onto which feature information is projected to a 2D image, providing an instant overview of the whole implant. The unfolding is made area-preserving when appropriate. These visualization methods facilitate better understanding of the bone-implant integration and provides a good platform for communication between involved experts.
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| 6. |
- Ballerini, Lucia, et al.
(författare)
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Comparison of histomorphometrical data obtained with two different image analysis methods
- 2007
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Ingår i: Journal of materials science. Materials in medicine. - : Springer. - 0957-4530 .- 1573-4838. ; 18:8, s. 1471-1479
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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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| 7. |
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| 8. |
- Johansson, Carina B., 1955-, et al.
(författare)
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Ex vivo and in vivo biomechanical test of implant attachment to various materials : introduction of a new user-friendly removal torque equipment
- 2012
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Ingår i: Clinical Implant Dentistry and Related Research. - : Wiley-Blackwell. - 1523-0899 .- 1708-8208. ; 14:4, s. 603-611
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 9. |
- Reigstad, O, et al.
(författare)
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Different patterns of bone fixation with hydroxyapatite and resorbable CaP coatings in the rabbit tibia at 6, 12, and 52 weeks
- 2011
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Ingår i: Journal of Biomedical Materials Research. Part B - Applied biomaterials. - : John Wiley & Sons. - 1552-4973 .- 1552-4981. ; 99B:1, s. 14-20
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Tidskriftsartikel (refereegranskat)abstract
- 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®) to a thin (40 μm) 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.
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| 10. |
- Thor, Andreas, et al.
(författare)
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Early bone formation in human bone grafts treated with platelet-rich plasma: preliminary histomorphometric results
- 2007
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Ingår i: INTERNATIONAL JOURNAL OF ORAL AND MAXILLOFACIAL SURGERY. - Amsterdam : Elsevier BV. - 0901-5027 .- 1399-0020. ; 36:12, s. 1164-1171
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this study was to evaluate the effect of platelet-rich plasma (PRP) on early and late bone healing after autogenous maxillary sinus grafting. Eleven patients were subjected to sinus augmentation with particulated autogenous bone bilaterally with the addition of PRP in one side. Platelet counts in baseline whole blood and PRP were registered. Biopsies were taken in the grafted bone of the sinus area with trephine at 3 months (nine patients) and simultaneously a micro-implant was installed in the same region. The micro-implants with surrounding bone were retrieved by biopsy at 6 months (seven patients). Undecalcified cut and ground sections were histomorphometrically analysed. Quantification of new and old bone in all biopsies was performed. The results of this histological study showed that significantly more new bone was formed at PRP-treated sites compared to controls after 3 months of healing. After 6 months, this effect could no longer be observed. This is in accordance with previous studies showing that PRP has a rather low regenerative capacity but may influence the early phase of bone healing. The additional value of PRP in autogenous bone grafts in the maxillary sinus is questionable.
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