title: Porous hydroxyapatite for grafting the maxillary sinus: a comparative histomorphometric study in sheep.
abstract: OBJECTIVE
  This experimental study in adult female sheep examined the value of nonresorbable porous hydroxyapatite (HA) as a grafting material in a single-stage sinus-lift procedure.
  
  
  METHODS
  Two titanium plasma-flame-sprayed cylindric implants were placed bilaterally in each of 54 sinuses in 27 adult female sheep. In 2 groups of 18 sinuses each, the subantral hollow space was filled with porous HA or autogenous cancellous bone harvested from the iliac crest, respectively. Eighteen sinuses were not augmented and served as controls. The time course of new bone formation and bone remodeling was evaluated by sequential polyfluorochrome labeling. Observation periods were 12, 16, and 26 weeks after the surgical procedure. Six sinuses per observation period and test group were available for histologic evaluation.
  
  
  RESULTS
  All implants were osseointegrated in the local host bone. New bone formation was observed in a triangular area bounded by the implant surface, local buccal antral wall, and submucous connective tissue around all implants. The mean length of bone-implant contact was 3.9 +/- 0.3 mm in the control group, 5.7 +/- 0.3 mm in the autogenous bone group, and 5.9 +/- 0.3 mm in the group augmented with porous HA. During the observation period, the relative length of direct bone-implant contact increased from 20% to 25.1% in the control group, from 30.4% to 35.5% in the autogenous bone group, and from 29.8% to 41.7% in the HA group. At a distance of 1 mm from the implant, the mean bone volume was 29.7 +/- 15.7% in the autogenous bone group. In the group augmented with HA the mean bone volume was 11.2 +/- 13.0%.
  
  
  CONCLUSIONS
  There was no significant difference between HA and autogenous bone regarding bone-implant contact (P = .89).
  
  
  CONCLUSIONS
  Both groups showed a significantly greater bone-implant contact (HA: P = .002; autogenous bone: P = .0005) than the empty control group. However, since the results varied widely, the use of HA alone for sinus grafting should be used with discretion in sinus-lift procedures.
authors.affiliation: Department of Oral Surgery, Dental School, University of Vienna, Austria. robert.haas@univie.ac.at
authors.forename: Robert
authors.initials: R
authors.lastname: Haas
authors.forename: Monika
authors.initials: M
authors.lastname: Baron
authors.forename: Karl
authors.initials: K
authors.lastname: Donath
authors.forename: Werner
authors.initials: W
authors.lastname: Zechner
authors.forename: Georg
authors.initials: G
authors.lastname: Watzek
mesh_terms: D000540:Alveolar Ridge Augmentation / Q000379:methods; D000704:Analysis of Variance; D000818:Animals; D001672:Biocompatible Materials / Q000737:chemistry / Q000627:therapeutic use*; D016723:Bone Remodeling / Q000502:physiology; D018786:Bone Substitutes / Q000737:chemistry / Q000627:therapeutic use*; D016025:Bone Transplantation; D003238:Connective Tissue / Q000473:pathology; D015921:Dental Implants; D017886:Durapatite / Q000737:chemistry / Q000627:therapeutic use*; D005260:Female; D005456:Fluorescent Dyes; D008437:Maxilla / Q000473:pathology / Q000601:surgery; D008443:Maxillary Sinus / Q000473:pathology / Q000601:surgery*; D016348:Osseointegration; D010012:Osteogenesis / Q000502:physiology; D016062:Porosity; D012756:Sheep; D013223:Statistics as Topic; D013499:Surface Properties; D013997:Time Factors; D014025:Titanium
chemical_list: D001672:Biocompatible Materials; D018786:Bone Substitutes; D015921:Dental Implants; D005456:Fluorescent Dyes; D017886:Durapatite; D014025:Titanium