Bone response to free-form fabricated hydroxyapatite and zirconia scaffolds: a transmission electron microscopy study in the human maxilla.
BACKGROUND
Understanding the interfacial reactions to synthetic bone regenerative scaffolds in vivo is fundamental for improving osseointegration and osteogenesis. Using transmission electron microscopy, it is possible to study the biological response of hydroxyapatite (HA) and zirconia (ZrO(2) ) scaffolds at the nanometer scale.


OBJECTIVE
In this study, the bone-bonding abilities of HA and ZrO(2) scaffolds produced by free-form fabrication were evaluated in the human maxilla at 3 months and 7 months.


METHODS
HA and ZrO(2) scaffolds (ø: 3 mm) were implanted in the human maxilla, removed with surrounding bone, embedded in resin, and sectioned. A novel focused ion beam (FIB) sample preparation technique enabled the production of thin lamellae for study by scanning transmission electron microscopy.


RESULTS
Interface regions were investigated using high-angle annular dark-field imaging and energy-dispersive X-ray spectroscopy analysis. Interfacial apatite layers of 80 nm and 50 nm thickness were noted in the 3- and 7-month HA samples, respectively, and bone growth was discovered in micropores up to 10 µm into the samples.


CONCLUSIONS
The absence of an interfacial layer in the ZrO(2) samples suggest the formation of a direct contact with bone, while HA, which bonds through an apatite layer, shows indications of resorption with increasing implantation time. This study demonstrates the potential of HA and ZrO(2) scaffolds for use as bone regenerative materials.
Department of Engineering Sciences, The Ångström Laboratory, Uppsala University, Uppsala, Sweden. kathryn.grandfield@angstrom.uu.se
Kathryn
K
Grandfield
Anders
A
Palmquist
Fredric
F
Ericson
Johan
J
Malmström
Lena
L
Emanuelsson
Christer
C
Slotte
Erik
E
Adolfsson
Gianluigi A
GA
Botton
Peter
P
Thomsen
Håkan
H
Engqvist
D000328:Adult; D000368:Aged; D001672:Biocompatible Materials / Q000737:chemistry; D001861:Bone Regeneration / Q000502:physiology*; D018786:Bone Substitutes / Q000737:chemistry; D017886:Durapatite / Q000737:chemistry; D004867:Equipment Design; D005260:Female; D006801:Humans; D008297:Male; D008422:Materials Testing; D008437:Maxilla / Q000601:surgery; D046529:Microscopy, Electron, Transmission; D008875:Middle Aged; D058608:Nanopores; D016062:Porosity; D013052:Spectrometry, X-Ray Emission; D013499:Surface Properties; D054457:Tissue Scaffolds; D055815:Young Adult; D015040:Zirconium / Q000737:chemistry
D001672:Biocompatible Materials; D018786:Bone Substitutes; D017886:Durapatite; D015040:Zirconium; C028541:zirconium oxide