title: Histological Comparison of New Biodegradable Magnesium-Based Implants for Maxillofacial Applications.
abstract: BACKGROUND
  A variety of materials have been used for bone augmentation, distraction osteotomy, and in post-cancer patients following tumor removal. However, a temporary metal implant that would resorb after successful treatment is a new concept. Magnesium was suggested as a suitable material for these purposes because it is biocompatible, has better mechanical properties than titanium, and stimulates new bone formation. This study evaluates histological appearance of magnesium-based implants and the surrounding bone.
  
  
  METHODS
  Three magnesium-based biomaterials were tested in a rabbit bone defect model: magnesium-hydroxyapatite (Mg-HA), W4 (96 % magnesium, 4 % yttrium), and pure magnesium (pure Mg). Animals were sacrificed after 6 and 12 weeks and the samples were analyzed histologically and histomorphometrically.
  
  
  RESULTS
  Mg-HA had the highest mean amount of tartrate-resistant acid phosphatase (TRAP) positive cells at the implantation site of all groups. It had shown the fastest degradation rate already at 6 weeks but the least amount of new bone formation. New bone was seen forming in direct contact with pure Mg and W4. The mean gas volume was highest in W4 compared to pure Mg and Mg-HA but this difference was not statistically significant. W4 had the lowest mean number of TRAP-positive cells of all materials.
  
  
  CONCLUSIONS
  Pure Mg and W4 were shown to be the most promising materials in this study in respect to the bone response to the implant material. They could be used for screws and plates in bone augmentation procedures.
authors.affiliation: BFS, Laboratory for Experimental Trauma Surgery, Justus-Liebig University Giessen, Schubertstrasse 81, 35392 Giessen, Germany.|aap Biomaterials GmbH, Lagerstrasse 11-15, 64807 Dieburg, Germany.
authors.forename: Olga
authors.initials: O
authors.lastname: Charyeva
authors.affiliation: BFS, Laboratory for Experimental Trauma Surgery, Justus-Liebig University Giessen, Schubertstrasse 81, 35392 Giessen, Germany.|Department of Trauma Surgery, University Hospital of Giessen-Marburg, Rudolf-Buchheim-Str. 9, 35385 Giessen, Germany.
authors.forename: Ulrich
authors.initials: U
authors.lastname: Thormann
authors.affiliation: BFS, Laboratory for Experimental Trauma Surgery, Justus-Liebig University Giessen, Schubertstrasse 81, 35392 Giessen, Germany.
authors.forename: Katrin S
authors.initials: KS
authors.lastname: Lips
authors.affiliation: aap Biomaterials GmbH, Lagerstrasse 11-15, 64807 Dieburg, Germany.
authors.forename: Lydia
authors.initials: L
authors.lastname: Heimann
authors.affiliation: BFS, Laboratory for Experimental Trauma Surgery, Justus-Liebig University Giessen, Schubertstrasse 81, 35392 Giessen, Germany.
authors.forename: Ursula
authors.initials: U
authors.lastname: Sommer
authors.affiliation: Department of Trauma Surgery, University Hospital of Giessen-Marburg, Rudolf-Buchheim-Str. 9, 35385 Giessen, Germany.
authors.forename: Gabor
authors.initials: G
authors.lastname: Szalay
authors.affiliation: BFS, Laboratory for Experimental Trauma Surgery, Justus-Liebig University Giessen, Schubertstrasse 81, 35392 Giessen, Germany.|Department of Trauma Surgery, University Hospital of Giessen-Marburg, Rudolf-Buchheim-Str. 9, 35385 Giessen, Germany.
authors.forename: Volker
authors.initials: V
authors.lastname: Alt
authors.affiliation: Magnesium Innovation Centre, Helmholtz-Zentrum Geesthacht, Max-Planck-Str. 1, 21502 Geesthacht, Germany.
authors.forename: Norbert
authors.initials: N
authors.lastname: Hort
authors.affiliation: BFS, Laboratory for Experimental Trauma Surgery, Justus-Liebig University Giessen, Schubertstrasse 81, 35392 Giessen, Germany.|Department of Trauma Surgery, University Hospital of Giessen-Marburg, Rudolf-Buchheim-Str. 9, 35385 Giessen, Germany.
authors.forename: Reinhard
authors.initials: R
authors.lastname: Schnettler
authors.affiliation: Orthopaedic University Hospital Friedrichsheim, Marienburgstr. 2, 60528 Frankfurt on Main, Germany.
authors.forename: Michael
authors.initials: M
authors.lastname: Rauschmann
authors.affiliation: Orthopaedic University Hospital Friedrichsheim, Marienburgstr. 2, 60528 Frankfurt on Main, Germany.
authors.forename: Sven
authors.initials: S
authors.lastname: Schmidt
keywords: Biocompatibility; Biodegradability biomaterials; Magnesium