Osseointegration of dental PEEK implants: A combined MRI and histology study
Cindy Elschner1, Matthias C. Schulz2, Ursula Range3, Ulrich Scheler1, Paula Korn2 Leibniz-Institut für Polymerforschung Dresden e.V., Hohe Str. 6, 01069 Dresden 2 Klinik und Poliklinik für Mund-, Kiefer- und Gesichtschirurgie, Universitätsklinikum „Carl Gustav Carus“, Fetscherstr. 74, 01307 Dresden 3 Institut für Medizinische Informatik und Biometrie, Universitätsklinikum „Carl Gustav Carus“, Blasewitzer Str. 86, 01307 Dresden 1
Contribution
Research issues healing of dental implants using
The study3 evaluated the osseous
Histological evaluation is the established Gold standard in implant research. However, these techniques are time-
MRI and histology in parallel. The direct comparison of the results
consuming, destructive and therefore only a limited number of sections can be analysed. The
obtained from both techniques allowed assessing the following
investigation of non-destructive 3D imaging techniques that enable the analysis of osseointegration
3 questions:
of biomaterials is of great interest for preclinical research. MRI as powerful tool for soft tissue imaging is not currently used in the field of implantology. The present study evaluated the suitability of MRI
A) Are there comparable results between MRI and histology?
to assess peri-implant bone formation of a dental implant in an animal model. PEEK was chosen
as implant material, since it is actually discussed as promising alternative to titanium and due to its compatibility to medical
.
imaging1,2
Experimental part
⦁ minipig, ⦁ 3 animals, ⦁ analysis after 2, 4 & 8 weeks
⦁ material: polyetheretherketone (PEEK) ⦁ coating with Ti layer (100 nm)4 ⦁ size: 11.0 mm (length), 4.5 mm (diameter) ⦁ incl. additional cavity (ROI 1)
C) Do the dental implants expose a sufficient osseointegration?
Monitoring
Animal model:
Dental implant:
B) Are there additional information with multimodal analysis?
MRI & histology, overview images
Tomographic views MRI slice images after 2 weeks
Histology: ⦁ Donath‘s sawing & grinding technique ⦁ Masson-Goldner-Trichrome stain
MRI examination: ⦁ 7-T BrukerAvance nonclinical NMR spectrometer ⦁ proton density & T1 weighting ⦁ resolution: 0.04 x 0.08 mm (longitudinal), 0.03 x 0.06 mm (axial) ⦁ slice thickness: 0.125 mm
(green: mineralized tissue; red-orange: osteoid; orange: soft tissue)
Scale bars on the magnifications: 0.5 mm
Summary
Answers of the 3 questions:
MRI evaluation with three chosen axial views
A) Yes; no significant differences between quantitative results from histomorphometry
Analysis:
quantitative MRI & histomorphometry ⦁ 4 ROIs ⦁ 4 parameter: bone volume density (BVD),
Superimposed image
and MRI
B) Yes; MRI quantification of fatty tissue/bone marrow
soft tissue volume density (SVD), osteoid tissue (OT, Histo), fatty tissue/bone marrow (FT, MRI)
Histology upon MRI slice image
(indication of bone maturation); assessment of osteoid tissue content with histomorphometry
C) Yes; uneventful healing; no signs of inflammation; BVDs increased up to 20 % in all ROIs; but slight deformation of the threads (low elastic modulus of PEEK (3.6 GPa)); did not alter bone formation) Scale bars: 1.0 mm
Quantification Principle of quantitative MRI
Comparison of MRI results with histomorphometry
Summary of histological and MRI quantification for all ROIs
⦁ overall soft tissue: proton density images; treshold = 3 x noise ⦁ fatty tissue: T1 weighted images accentuate fatty tissue; distinct treshold between fatty tissue & „residual“ soft tissue
📖 References 📧
[email protected]
Kurtz, S. M.; Devine, J. N. Biomaterials 2007, 28, 4845–4869. 2 Kistler, F.; Kistler, S.; Neugebauer, J. Implantologie Journal 2013, 7, 42–50. 3 Elschner, C.; Schulz, M. C.; Range, U.; Mai, R.; Eckelt, U.; Scheler, U.; Korn, P. 2014, (in preparation). 4 Elschner, C.; Noack, C.; Preißler, C.; Krause, A.; Scheler, U.; Hempel, U. J Mater Sci Technol 2014, (in press). 1
💰 Funding ESF grant & SFB/TRR 67 (B6/B8)
