Torben Hildebrand

• Rubenis, Kristaps; He, Xin; Demir, Öznur; Fu, Zhaoyue; Sigurjónsson, Ólafur Eysteinn & Hildebrand, Torben [Show all 13 contributors for this article] (2026). Eggshell-derived amorphous calcium phosphate for upcycled bone repair: An In-Vivo study. Materials Today Communications. 53. doi: 10.1016/j.mtcomm.2026.115391. Full text in Research Archive Show summary

  Critical-sized bone defects require grafting materials that support early osteogenesis and predictable defect bridging. In this study, we evaluated eggshell-derived amorphous calcium phosphate (ACP) granules in a rat calvarial defect model and compared them with ACP obtained from commercial hydroxyapatite (HAp) and with cross-linked hyaluronic acid (HA) gel alone. Eggshell-derived and HAp-derived ACP were synthesized by the same dissolution–precipitation route, using formulations previously characterized in detail for composition, amorphous phase stability, and in vitro bioactivity. Bilateral 5 mm calvarial defects in rats were filled with HA gel (INT/HA), HA + HAp-derived ACP (Control ACP), or HA + eggshell-derived ACP (Eggshell ACP). Grafts were mixed immediately before implantation using a dual-syringe system. Bone regeneration at 2 and 4 weeks was assessed by micro-computed tomography and histology. Both ACP-containing groups enhanced bone volume fraction and reduced trabecular separation compared with HA alone, particularly in the central region of the defect. Eggshell ACP promoted more consistent defect bridging, with a continuous lamellar bone-like layer and more mature collagenous and mineralized tissue at the bone–graft interface. Within the limitations of a non-load-bearing small-animal model, these findings indicate that eggshell-derived ACP combined with HA supports early bone regeneration and exhibits higher osteogenic activity than HA alone and HAp-derived ACP, warranting further investigation as a bone graft candidate.

• Procházková, Petra; Parobková, Viktória; Hildebrand, Torben; Nogueira, Liebert Parreiras; Vrlíková, Lucie & Buchtová, Marcela [Show all 8 contributors for this article] (2026). Contrast Agents and Sample Preparation Strategies for Soft Tissue Imaging in X-ray Computed Microtomography: Review and Experimental Validation in Mouse Tissues. Tomography of Materials and Structures (JTMS). 11. doi: 10.1016/j.tmater.2026.100086. Full text in Research Archive Show summary

  Micro-computed tomography (micro-CT) is an effective technique for non-destructive high-resolution imaging of mineralized tissues; however, imaging of soft tissues is challenging due to their inherently low X-ray attenuation and poor contrast. Therefore, their visualization in absorption micro-CT requires the use of contrast agents (CA) such as iodine-based solutions, osmium tetroxide, phosphotungstic acid, and other polyoxometalates. The aim of this review is to outline the individual steps of sample preparation before micro-CT measurement, such as fixation, dehydration, and contrast enhancement of soft tissues, and summarize the most commonly used CAs in ex vivo visualization. In addition to the literature overview, we conducted comparative staining experiments on mouse organs using several widely applied CAs, with the aim of illustrating practical outcomes and challenges. Based on both the data published and our test results, we recommend the most suitable CAs for different tissue types, with emphasis on minimizing tissue damage and deformation, and devote particular attention to applications in mouse embryos.

• Ma, Qianli; Staudigel, Katrin Anja; Rubenis, Kristaps; Fu, Zhaoyue; Hildebrand, Torben & Zaldenieks, Markuss [Show all 12 contributors for this article] (2026). Sustainable Eggshell-Based Amorphous Calcium Phosphate Scaffolds and Membrane Protein Hydrogel for Regeneration in Rabbit Femoral and Calvarial Defects. ACS Applied Materials & Interfaces. ISSN 1944-8244. doi: 10.1021/acsami.5c25453. Full text in Research Archive Show summary

  Critical-sized bone defects require grafts with ideal spatial supporting. We upcycled eggshell waste sustainably into porous amorphous calcium phosphate (ACP) scaffolds and evaluated their early bone-regeneration performance alone and in combination with flexible and bioactive adjuncts in vivo. ACP scaffolds with ∼60% porosity were fabricated by pressure-densification, using ice microspheres as space holders. Before implantation, ACP scaffolds were vacuum-infiltrated with a hyaluronic acid (HA) hydrogel to minimize internal voids. Bilateral critical-size femoral and calvarial defects were created in New Zealand White rabbits and reconstructed with one of four treatments: (1) Sham, (2) ACP scaffold (ACP), (3) ACP infused with HA hydrogel containing a proline-rich peptide P2 (ACP + HA/P2), or (4) ACP infused with HA/P2 supplemented with soluble eggshell membrane proteins (prepared by our lab, ACP + HA/P2 + SEPs). After 6 weeks, micro-CT and histology were performed. All ACP-containing groups showed greater defect filling and mineralization than the Sham group. Micro-CT analysis demonstrated that ACP + HA/P2 + SEPs achieved the highest bone volume and trabecular number and the lowest trabecular separation. Histology confirmed more extensive mineralized collagenous deposition on ACP scaffolds and a more integrated bone–material fusion zone in this group. In femoral defects with graft displacement, ACP scaffolds induced cortical–scaffold bone bridging within the marrow, most evident with SEPs. Eggshell-derived ACP scaffolds, particularly when paired with SEP-enriched HA hydrogel, enhance early regeneration of critical-sized bone defects. Upcycling the inorganic and organic constituents of eggshell waste yields a complementary, single-origin biomaterials package for sustainable bone repair.

• Nysæther, Ingvild; Haugen, Håvard Jostein; Khassawna, Thaqif El; Jamous, Reem; Afnan, Shoresh & Santacroce, Marco [Show all 10 contributors for this article] (2025). Clinical Performance of Ultra‐Porous TiO2 Scaffold as Bone Graft Substitute in Human Alveolar Ridge Preservation—A Feasibility Study. Clinical Oral Implants Research. ISSN 0905-7161. doi: 10.1111/clr.70074. Full text in Research Archive Show summary

  Objectives This study evaluates the safety and osteoconductive potential of a ceramic TiO2 scaffold in human alveolar bone, hypothesising that placement in human extraction sockets is safe, supports bone ingrowth and preserves ridge dimensions. Material and Methods Nine subjects requiring the extraction of ≥ 1 premolar or molar tooth were enrolled. Full-thickness mucoperiosteal flaps were elevated. Following tooth extraction, porous ceramic TiO2 scaffolds were adjusted chair-side, placed into the extraction socket and covered by a resorbable collagen membrane. After 6 months of healing, before dental implant placement, a biopsy was performed at the site where the scaffold had been placed. Histomorphometric and micro-CT analyses were made. CBCT images were made at baseline and at 6 months to assess alveolar ridge dimensional changes. Implants placed in regenerated bone were followed for 21 months. Results Scaffold customisation with chairside adjustment was straightforward. No serious adverse events were observed during the 6 months following scaffold implantation. One scaffold was removed due to an early exposure, while the remaining 9 scaffolds successfully integrated. Two sites presented with minor soft tissue dehiscences at 1–2 weeks, which healed spontaneously. Micro-CT and histology confirmed new bone formation. Soft tissue healing was favourable, with no adverse reactions. Dimensional analysis revealed minimal changes in alveolar ridge width and height, indicating effective preservation of volume. Conclusions This clinical study confirms that TiO2 scaffolds are a safe and effective option for promoting bone regrowth and preserving volume in human alveolar bone, thereby facilitating bone formation and maintaining ridge dimensions post-extraction.

• Gajski, Petra; Par, Matej; Haugen, Håvard Jostein; Hildebrand, Torben; Zheng, Kai & Boccaccini, Aldo R [Show all 8 contributors for this article] (2025). Long-Term Water Immersion of Dental Composites Based on Bioactive Glass Influence on Sorption, Solubility, and Porosity. Scientific Reports. 15, p. 18857–18857. doi: 10.1038/s41598-025-04143-9. Full text in Research Archive Show summary

  This study investigated the effect of copper-doped mesoporous bioactive glass nanospheres (Cu-MBGN) on water sorption, solubility and porosity of an experimental dental composite over 180 days of water immersion, comparing it to bioactive glass 45S5 (BG) or inert fillers. Composites contained 35wt% Bis-GMA/TEGDMA resin (60/40), 55wt% silanised barium-glass fillers, and 10wt% of either Cu-MBGN (10-CuBG), 45S5 bioactive glass (10-BG), or inert silica nanofillers (10-Si). Both BG composites showed a higher mass increase during water immersion than inert control (10-Si) at all measured time points (p < 0.001), ranked as 10-BG > 10-CuBG > 10-Si. After 30 days, 10-BG had the greatest mass increase (4.02 ± 0.21%), followed by a decline until 180 days, while 10-CuBG (1.67 ± 0.10%) and 10-Si (1.19 ± 0.07%) showed gradual mass increases until the end of the measurement. 10-BG displayed higher water sorption and solubility than other materials, while 10-CuBG had the highest porosity parameters. While 10-BG and 10-Si showed significant increases in both total and open porosity after water immersion, no such changes were observed for 10-CuBG. The pore characteristics of dry specimens did not affect final water sorption and solubility after 180 days of water immersion. The Cu-MBGN composite had a lower mass increase than commercial BG and met ISO 4049 standards for both water sorption and solubility.

• Hildebrand, Torben; Haugen, Håvard Jostein; Romandini, Mario; Plotino, Gianluca & Nogueira, Liebert Parreiras (2025). From Pulp to Cementum: 3D Visualization of Soft and Hard Dental Tissues Using Different Micro-CT Contrast-Enhancement Techniques. International Endodontic Journal. ISSN 0143-2885. doi: 10.1111/iej.14260. Full text in Research Archive Show summary

  Aim: To determine the effect of two contrast-enhancement strategies in nano-computed tomography (nano-CT) imaging on the contrast-to-noise ratio (CNR) of various dental tissues, including pulp, dentine and cementum, with the goal of enhancing the visibility of dental soft tissues to a level not yet reported in laboratory nano-CT imaging. Methodology: Ten sound human third molars underwent decalcification and subsequent treatment with Lugol’s iodine (n=5, Group 1) or phosphotungstic acid (PTA) treatment without prior decalcification (n=5, Group 2) for contrast enhancement. Imaging was performed using the laboratory nano-CT system Skyscan 2211 and the synchrotron radiation for medical physics (SYRMEP) beamline. CNRs were measured for pulpal tissue, dentine and cementum and nano-CT images were compared with classical histology, scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDXS). Results: Group 1 significantly enhanced the contrast of pulp tissue, resulting in a 168.2 % increase due to decalcification and an additional 148.7 % increase after Lugol’s iodine treatment. Dentine exhibited higher contrast in Group 2, whereas cementum showed similar contrast across both groups. Laboratory nano-CT enabled the visualisation of detailed soft tissue structures, including nerves, blood vessels and odontoblasts within the pulp, but cementocytes remained not visibleinvisible. Conclusions: Decalcification followed by Lugol’s iodine treatment was superior for enhancing soft tissue contrast, especially for pulp visualisation. PTA without decalcification yielded better contrast for dentine and facilitated the visualisation of attached soft tissues, such as periodontal ligament and predentine. These findings provide insights into selecting the most appropriate protocol to optimise nano-CT imaging for specific dental tissue analyses, including the pulp.

• Hildebrand, Torben; Ma, Qianli; Loča, Dagnija; Rubenis, Kristaps; Locs, Janis & Nogueira, Liebert Parreiras [Show all 7 contributors for this article] (2024). Improved visualisation of ACP-engineered osteoblastic spheroids: a comparative study of contrast-enhanced micro-CT and traditional imaging techniques. Biofabrication. ISSN 1758-5082. 17(1). doi: 10.1088/1758-5090/ad8bf5. Full text in Research Archive Show summary

  This study investigates osteoblastic cell spheroid cultivation methods, exploring flat-bottom, U-bottom, and rotary flask techniques with and without amorphous calcium phosphate (ACP) supplementation to replicate the 3D bone tissue microenvironment. ACP particles derived from eggshell waste exhibit enhanced osteogenic activity in 3D models. However, representative imaging of intricate 3D tissue-engineered constructs poses challenges in conventional imaging techniques due to notable scattering and absorption effects in light microscopy, and hence limited penetration depth. We investigated contrast-enhanced micro-CT as a methodological approach for comprehensive morphological 3D-analysis of the in-vitro model and compared the technique with confocal laser scanning microscopy (CLSM), scanning electron microscopy (SEM) and classical histology. Phosphotungstic acid (PTA) and iodine-based contrast agents were employed for micro-CT imaging in laboratory and synchrotron micro-CT imaging. Results revealed spheroid shape variations and structural integrity influenced by cultivation methods and ACP particles. The study underscores the advantage of 3D spheroid models over traditional 2D cultures in mimicking bone tissue architecture and cellular interactions, emphasising the growing demand for novel imaging techniques to visualise 3D tissue-engineered models. Contrast-enhanced micro-CT emerges as a promising non-invasive imaging method for tissue-engineered constructs containing ACP particles, offering insights into sample morphology, enabling virtual histology before further analysis.

• Hildebrand, Torben; Ma, Qianli; Heyward, Catherine Anne; Haugen, Håvard Jostein & Nogueira, Liebert Parreiras (2024). Advanced soft tissue visualization in conjunction with bone structures using contrast-enhanced micro-CT. Journal of Medical Imaging. ISSN 2329-4302. 11(6). doi: 10.1117/1.JMI.11.6.066001. Full text in Research Archive Show summary

  Purpose: Micro-CT analysis of soft tissues alongside bone remains challenging due to significant differences in X-ray absorption, preventing spatial inspection of bone remodeling including the cellular intricacies of mineralized tissues in developmental biology and pathology. The goal was to develop a protocol for contrast-enhanced micro-CT imaging that effectively visualizes soft tissues and cells in conjunction with bone while minimizing bone attenuation by decalcification. Approach: Murine femur samples were decalcified in EDTA and treated with three different contrast agents: i) iodine in ethanol, ii) PTA in water, and iii) Lugol’s iodine. Micro-CT scans were performed in the laboratory set-up SkyScan 1172 and at the SYRMEP beamline in ELETTRA. Soft- and hard-tissue contrast-to-noise ratio (CNR) and contrast efficiency after decalcification were measured. Results: In laboratory micro-CT, Lugol’s iodine demonstrated a three-times higher CNR in bone marrow, representing the soft tissue portion, compared to bone. Contrast efficiencies, measured in synchrotron micro-CT, were consistent with these findings. Higher resolutions and the specificity of Lugol’s iodine to cellular structures enabled detailed visualization of bone-forming cells in the epiphyseal plate. Conclusions: The combination of decalcification and the utilization of the contrast agent Lugol’s iodine facilitated an enhanced soft tissue visualization in conjunction with bone.

• Hildebrand, Torben; Humphris, Yolanda; Haugen, Håvard Jostein & Nogueira, Liebert Parreiras (2024). Contrast-enhanced Micro-CT Imaging of Murine Mandibles: A Multimethod Approach for Simultaneous Hard and Soft Tissue Analysis. Journal of Clinical Periodontology. ISSN 0303-6979. p. 1–10. doi: 10.1111/jcpe.14077. Full text in Research Archive Show summary

  Aim To develop and evaluate a novel multi-method micro-computed tomography (μCT) imaging protocol for enhanced visualization of both hard and soft tissues in murine mandibles, addressing the limitations of traditional imaging techniques in dental research. Materials and Methods We employed a contrast-enhanced (CE) μCT imaging technique using Lugol's iodine as a contrast agent to visualize the intricate structures of murine mandibles. The protocol involved the combination of conventional μCT imaging as well as CE-μCT, including decalcification with EDTA, allowing for simultaneous assessment of hard and soft tissues. The method is compared with standard imaging modalities, and the ability to visualize detailed anatomical features is discussed. Results The CE-μCT imaging technique provided superior visualization of murine mandibular structures, including dental pulp, periodontal ligaments and the surrounding soft tissues, along with conventional μCT imaging of alveolar bone and teeth. This method revealed detailed anatomical features with high specificity and contrast, surpassing traditional imaging approaches. Conclusion Our findings demonstrate the potential of CE-μCT imaging with Lugol's iodine as a powerful tool for dental research. This technique offers a comprehensive view of the murine mandible, facilitating advanced studies in tissue engineering, dental pathology and the development of dental materials.

• Lemonche, Gerard Boix; Hildebrand, Torben; Haugen, Håvard Jostein; Petrovski, Goran & Nogueira, Liebert Parreiras (2024). Contrast-enhanced Micro-CT 3D visualization of cell distribution in hydrated human cornea. Heliyon. 10(3). doi: 10.1016/j.heliyon.2024.e25828. Full text in Research Archive Show summary

  Background The cornea, a vital component of the human eye, plays a crucial role in maintaining visual clarity. Understanding its ultrastructural organization and cell distribution is fundamental for elucidating corneal physiology and pathology. This study comprehensively examines the microarchitecture of the hydrated human cornea using contrast-enhanced micro-computed tomography (micro-CT). Method Fresh human corneal specimens were carefully prepared and hydrated to mimic their in vivo state. Contrast enhancement with Lugol's iodine-enabled high-resolution Micro-CT imaging. The cells' three-dimensional (3D) distribution within the cornea was reconstructed and analyzed. Results The micro-CT imaging revealed exquisite details of the corneal ultrastructure, including the spatial arrangement of cells throughout its depth. This novel approach allowed for the visualization of cells' density and distribution in different corneal layers. Notably, our findings highlighted variations in cell distribution between non-hydrated and hydrated corneas. Conclusions This study demonstrates the potential of contrast-enhanced micro-CT as a valuable tool for non-destructive, 3D visualization and quantitative analysis of cell distribution in hydrated human corneas. These insights contribute to a better understanding of corneal physiology and may have implications for research in corneal diseases and tissue engineering.

• Ma, Qianli; Rubenis, Kristaps; Sigurjonsson, Olafur E.; Hildebrand, Torben; Standal, Therese & Zemjane, Signe [Show all 9 contributors for this article] (2023). Eggshell-derived amorphous calcium phosphate: Synthesis, characterization and bio-functions as bone graft materials in novel 3D osteoblastic spheroids model. Smart Materials in Medicine. 4, p. 522–537. doi: 10.1016/j.smaim.2023.04.001. Full text in Research Archive Show summary

  A multitude of autogenous/allogeneic and semi-synthetic bone graft materials have been developed to reconstruct the defective bone tissue but with high bio-cost and potential environmental pollution. With high calcium content and several trace elements, chicken eggshells are no longer considered as wastes but attractive sources of high-value-added biomaterials. This study used chicken eggshells and synthetic hydroxyapatite (HAp) to synthesize amorphous calcium phosphate (ACP) bone graft materials, namely Control and Eggshell. The physiochemical characteristics, biosafety, and immunocompatibility of synthetic ACP particles were inspected. Their osteogenic activity was further investigated in a novel osteoblastic spheroids model. Eggshell ACP particles exhibited ideal cytocompatibility compared to the control ACP and were more resistant to re-crystallization. In osteoblastic spheroids, Eggshell ACP mediated typical osteogenic mRNA profiles of MC-3T3-E1 cells, accompanied by the increased formation of mineralized nodules and boosted synthesis of ECM proteins represented by OPN and collagen I. This study establishes a promising technique to synthesize stable, safe, and osteoinductive ACP graft particles from eggshell waste. Furthermore, the osteoblastic spheroids constructed in the present study provide a more practical model for biomaterial research, which reflect the three-dimensional interaction between host bone tissue and graft materials more realistically.

• Hildebrand, Torben; Novak, Jan; Nogueira, Liebert Parreiras; Boccaccini, Aldo Roberto & Haugen, Håvard Jostein (2023). Durability assessment of hydrogel mountings for contrast-enhanced micro-CT. Micron. ISSN 0968-4328. 174. doi: 10.1016/j.micron.2023.103533. Full text in Research Archive Show summary

  Micro-computed tomography (micro-CT) provides valuable data for studying soft tissue, though it is often affected by sample movement during scans and low contrast in X-ray absorption. This can result in lower image quality and geometric inaccuracies, collectively known as 'artefacts'. To mitigate these issues, samples can be embedded in hydrogels and enriched with heavy metals for contrast enhancement. However, the long-term durability of these enhancements remains largely unexplored. In this study, we examine the effects of two contrast enhancement agents – iodine and phosphotungstic acid (PTA) – and two hydrogels – agarose and Poloxamer 407 – over a 14-day period. We used Drosophila melanogaster as a test model for our investigation. Our findings reveal that PTA and agarose are highly durable, while iodine and poloxamer hydrogel exhibits higher leakage rates. These observations lay the foundation for estimating contrast stabilities in contrast-enhanced micro-CT with hydrogel embedding and serve to inform future research in this field.

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• Hildebrand, Torben; Ma, Qianli; Loca, Dagnija; Rubenis, Kristaps; Locs, Janis & Nogueira, Liebert Parreiras [Show all 7 contributors for this article] (2025). Contrast-enhanced Micro-CT for improved visualization of ACP-Engineered Osteoblastic Spheroids. Full text in Research Archive Show summary

  Introduction: Bone tissue engineering (TE) aims to develop biomaterials that replicate the specific mechanical strength essential for the functional characteristics of the bone. Osteoblastic spheroids provide a three-dimensional (3D) culture model that better mimics in vivo conditions than traditional two-dimensional (2D) cultures. Amorphous calcium phosphate (ACP), derived from eggshell waste, has shown enhanced osteogenic potential, making it a promising biomaterial for TE applications. However, due to limited penetration depth and structural distortion, conventional imaging techniques such as confocal microscopy and histology pose challenges in visualizing 3D constructs. This study evaluates contrast-enhanced micro-computed tomography (micro-CT) as a non-invasive alternative for 3D morphological analysis of ACP-engineered osteoblastic spheroids. Methods: Osteoblastic spheroids were cultivated using flat-bottom, U-bottom, and rotary flask techniques. Spheroids were supplemented with ACP derived from eggshell waste and synthesized ‘control’ ACP to assess its effects on osteogenic differentiation. Contrast-enhanced micro-CT imaging was performed using phosphotungstic acid (PTA) and iodine-based contrast agents. Scans were performed with a laboratory nano-CT (SkyScan 2211 Multiscale x-ray Nano-CT System, Bruker) and at the Synchrotron Radiation for Medical Physics (SYRMEP) beamline in the synchrotron laboratory ELETTRA (Trieste, Italy). Imaging results were compared with confocal laser scanning microscopy, scanning electron microscopy, and classical histology. Results: The cultivation method significantly influenced spheroid morphology, with rotary flask cultivation producing the most structurally uniform spheroids. ACP incorporation enhanced osteogenic activity and spheroid integrity and altered the spheroids’ morphology in volume and roundness. Contrast-enhanced micro-CT provided superior overall visualization of the spheroid and of internal architecture, allowing detailed analysis of cell and ACP distribution and matrix deposition. Unlike traditional imaging techniques, micro-CT enabled virtual histology without sectioning artifacts or depth limitations. Discussion: This study underscores the need for advanced imaging modalities to evaluate engineered tissues effectively. Contrast-enhanced micro-CT offers a non-invasive, high-resolution approach for visualizing cellular interactions within biomaterials, addressing key limitations of conventional imaging techniques. The findings support the integration of ACP into bone TE strategies and demonstrate the potential of micro-CT for enhancing the assessment of biofabricated constructs, particularly for large cell models including a mineralized portion.

• Hildebrand, Torben; Ma, Qianli; A, Heyward Catherine; Haugen, Håvard Jostein & Nogueira, Liebert Parreiras (2024). Advanced soft tissue visualization in conjunction with bone structures using contrast-enhanced micro-CT. Full text in Research Archive
• Hildebrand, Torben; Lemonche, Gerard Boix; Haugen, Håvard Jostein; Petrovski, Goran & Nogueira, Liebert Parreiras (2024). Contrast-enhanced micro-CT for visualization of cell distribution in hydrated human cornea. Full text in Research Archive
• Ma, Qianli; Rubenis, Kristaps; Haugen, Håvard Jostein; Hildebrand, Torben; Sigurjonsson, Olafur E. & Locs, Janis [Show all 7 contributors for this article] (2024). Eggshell-derived Amorphous Calcium Phosphate: Synthesis, Characterization and Bio-functions as Bone Graft Materials in Novel 3d Osteoblastic Spheroidic Model. Full text in Research Archive
• Haugen, Håvard Jostein; Nogueira, Liebert Parreiras & Hildebrand, Torben (2023). Novel techniques to visualise cellular tissues using X-ray imaging. Full text in Research Archive
• Hildebrand, Torben (2025). Optimising Contrast-Enhanced Micro-CT Techniques for Comprehensive Visualisation of Dental Structures. Universitetet i Oslo. ISSN 9788283271003. Full text in Research Archive Show summary

  For å få bedre innsikt i samspillet mellom bløte og harde vev, og sykdommene som rammer dem, trenger vi gode avbildningsteknikker innen odontologisk og regenerativ forskning. Vanlig mikro-CT viser mineraliserte strukturer som emalje og dentin svært godt, men bløtvev fremstår kornete fordi røntgenkontrasten er lav. Med kontrastforsterket mikro-CT kan vi «farge» bløtvevet kjemisk og dermed hente frem detaljer i tre dimensjoner. Torben Hildebrand har i doktorgradsavhandlingen sin undersøkt hvordan vi kan presse laboratoriebaserte mikro-CT-systemer til å nærme seg bildekvaliteten fra veldig avanserte synkrotronbaserte metoder. Han har testet ulike kontrastmidler, blant annet jod og fosfortungstensyre, og sett på hvordan skånsom demineralisering kan gjøre grensen mellom ulike vevstyper tydeligere. Testmetodene er prøvd ut på mennesketenner, musekjever og kunstige vevskonstruksjoner. Resultatene viser at de forbedrede mikro-CT-oppsettene gir høyoppløselige bilder av både bløte og harde vev, slik at vi kan utføre «virtuell histologi» uten å snitte i prøvene. Metodene fungerer godt sammenlignet med tradisjonell histologi og synkrotronbilder. Denne tilnærmingen gjør avansert 3D-avbildning mer tilgjengelig og åpner nye muligheter innen odontologisk og regenerativ forskning.

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