title: Comparison of computed tomography and microradiography for graft evaluation after reconstruction of critical size bone defects using beta-tricalcium phosphate.
abstract: BACKGROUND
  The aim of the study was to evaluate the accuracy of computed tomography (CT) for in vivo follow up after mandibular reconstruction.
  
  
  METHODS
  Unilateral mandibular defects were surgically created in ten sheep and either reconstructed using blood soaked beta-tricalcium phosphate (beta-TCP) cylinders (group A, n=5) or blood soaked beta-TCP cylinders that were additionally loaded with autologous bone marrow (group B, n=5). The two graft designs resulted in different stages of graft ossification representative of different stages of healing. CT datasets were fused with microradiographs and measurements of ceramic area based on both methods were compared.
  
  
  RESULTS
  Two animals (groups A (n=1) and B (n=1)) presented infection and graft dislocation that was visible on CT and were excluded from statistical evaluation. Group A grafts underwent moderate degradation (53.55%+/-9.7) and incomplete bony incorporation representing an intermediate state of healing while ceramic grafts within group B developed a high grade of osseointegration and degradation (94.2%+/-3.3) consistent with progressive healing. Statistical comparison of measurements based on both methods revealed a significant bias (p<0.05) and a non-significant variance for group A and a significant variance (p<0.05) and non-significant bias for group B.
  
  
  CONCLUSIONS
  Our results indicate that conventional CT is not suitable to objectively evaluate ossification and degradation of a beta-TCP graft in vivo and further attempts to improve clinical visualization of beta-TCP need to be undertaken.
authors.affiliation: Department of Oral and Maxillofacial Surgery, Hannover Medical School, 30625 Hannover, Germany. mirja.nolff@tiho-hannover.de <mirja.nolff@tiho-hannover.de>
authors.forename: M C
authors.initials: MC
authors.lastname: Nolff
authors.forename: H
authors.initials: H
authors.lastname: Kokemueller
authors.forename: G
authors.initials: G
authors.lastname: Hauschild
authors.forename: M
authors.initials: M
authors.lastname: Fehr
authors.forename: K-H
authors.initials: KH
authors.lastname: Bormann
authors.forename: S
authors.initials: S
authors.lastname: Spalthoff
authors.forename: K
authors.initials: K
authors.lastname: Rohn
authors.forename: M
authors.initials: M
authors.lastname: Ruecker
authors.forename: N-C
authors.initials: NC
authors.lastname: Gellrich
mesh_terms: D000818:Animals; D001672:Biocompatible Materials / Q000494:pharmacology; D001861:Bone Regeneration / Q000187:drug effects*; D018786:Bone Substitutes / Q000494:pharmacology*; D002130:Calcium Phosphates / Q000494:pharmacology; D005260:Female; D006085:Graft Survival; D008334:Mandible / Q000000981:diagnostic imaging* / Q000601:surgery; D008852:Microradiography; D016348:Osseointegration; D017063:Outcome Assessment, Health Care / Q000379:methods; D012680:Sensitivity and Specificity; D012756:Sheep; D023822:Tissue Engineering; D054457:Tissue Scaffolds; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome; D014945:Wound Healing
chemical_list: D001672:Biocompatible Materials; D018786:Bone Substitutes; D002130:Calcium Phosphates; C485817:beta-tricalcium phosphate