title: Experimental studies on a new highly porous hydroxyapatite matrix for obliterating open mastoid cavities.
abstract: OBJECTIVE
  In an initial preliminary study, the applicability of a new high-porosity hydroxyapatite (HA) ceramic for obliterating large open mastoid cavities was proven and tested in an animal model (bulla of guinea pig).
  
  
  METHODS
  Experimental study.
  
  
  METHODS
  NanoBone, a highly porous matrix consisting of 76% hydroxyl apatite and 24% silicone dioxide fabricated in a sol-gel technique, was administered unilaterally into the opened bullae of 30 guinea pigs. In each animal, the opposite bulla was filled with Bio-Oss, a bone substitute consisting of a portion of mineral bovine bone. Histologic evaluations were performed 1, 2, 3, 4, 5, and 12 weeks after the implantation.
  
  
  RESULTS
  After an initial phase in which the ceramic granules were surrounded by inflammatory cells (1-2 wk), there were increasing signs of vascularization. Osteoneogenesis and-at the same time-resorption of the HA ceramic were observed after the third week. No major difference in comparison to the bovine bone material could be found.
  
  
  CONCLUSIONS
  Our results confirm the favorable qualities of the new ceramic reported in association with current maxillofacial literature. Conventional HA granules used for mastoid obliteration to date often showed problems with prolonged inflammatory reactions and, finally, extrusions. In contrast to those ceramics, the new material seems to induce more osteoneogenesis and undergoes early resorption probably due to its high porosity. Overall, it is similar to the bovine bone substance tested on the opposite ear in each animal. Further clinical studies may reveal whether NanoBone can be an adequate material for obliterating open mastoid cavities in patients.
authors.affiliation: Department of ENT, University of Rostock, Rostock, Germany. christoph.punke@med.uni-rostock.de
authors.forename: Christoph
authors.initials: C
authors.lastname: Punke
authors.forename: Thorsten
authors.initials: T
authors.lastname: Zehlicke
authors.forename: Carsten
authors.initials: C
authors.lastname: Boltze
authors.forename: Hans Wilhelm
authors.initials: HW
authors.lastname: Pau
mesh_terms: D000818:Animals; D001672:Biocompatible Materials / Q000008:administration & dosage / Q000494:pharmacology*; D017886:Durapatite / Q000008:administration & dosage / Q000494:pharmacology*; D006168:Guinea Pigs; D008416:Mastoid / Q000166:cytology / Q000187:drug effects* / Q000601:surgery; D016062:Porosity
chemical_list: D001672:Biocompatible Materials; D017886:Durapatite