title: Capability of new bone formation with a mixture of hydroxyapatite and beta-tricalcium phosphate granules.
abstract: OBJECTIVE
  The aim of this experimental study was to test a mixture of hydroxyapatite (HA) and beta-tricalcium phosphate (beta-TCP) granules inserted in cranial defects in rabbits, by the evaluation of the hard tissues volume, new bone formation, and residual graft after 4 and 8 weeks.
  
  
  METHODS
  Two defects of 8 mm diameter were created at the calvarial bone of 24 Japanese white rabbits for a total of 48 defects. Four groups were created: defects filled with a mixture of HA and beta-TCP granules (test A), defects filled with HA alone (test B), defects filled with beta-TCP (test C), and empty defects (control). Hard tissues volume (remaining graft + new bone) was evaluated by μ-CT and new bone (NB) and remaining graft (RG) percentages were evaluated by histomorphometry. The animals were sacrificed at 4 or 8 weeks postoperatively.
  
  
  RESULTS
  The test groups A, B, and C showed a significant higher total volume compared with controls at 4 and 8 weeks (P < 0.05). Regarding the percentages of NB and RG at 4 and 8 weeks, no significant differences were detected (P > 0.05). When comparing 4 and 8 weeks, test group A showed a significant increase in new bone formation. At both 4 and 8 weeks, no group showed significant differences in NB (P > 0.05). At 8 weeks, test group B had more RG than test group A.
  
  
  CONCLUSIONS
  The novel mixture could maintain the volume of the grafted area compared with that with intervention, and in a similar way compared with HA.
authors.affiliation: Department of Oral Implantology and Regenerative Dental Medicine, Tokyo Medical and Dental University, Tokyo, Japan.
authors.forename: Minoru
authors.initials: M
authors.lastname: Sanda
authors.affiliation: Department of Oral Implantology and Regenerative Dental Medicine, Tokyo Medical and Dental University, Tokyo, Japan.
authors.forename: Makoto
authors.initials: M
authors.lastname: Shiota
authors.affiliation: Department of Oral Implantology and Regenerative Dental Medicine, Tokyo Medical and Dental University, Tokyo, Japan.
authors.forename: Masaki
authors.initials: M
authors.lastname: Fujii
authors.affiliation: Department of Oral Implantology and Regenerative Dental Medicine, Tokyo Medical and Dental University, Tokyo, Japan.
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Kon
authors.affiliation: Department of Oral Implantology and Regenerative Dental Medicine, Tokyo Medical and Dental University, Tokyo, Japan.
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Fujimori
authors.affiliation: Department of Oral Implantology and Regenerative Dental Medicine, Tokyo Medical and Dental University, Tokyo, Japan.
authors.forename: Shohei
authors.initials: S
authors.lastname: Kasugai
mesh_terms: D000818:Animals; D002130:Calcium Phosphates / Q000494:pharmacology*; D017886:Durapatite / Q000494:pharmacology*; D008297:Male; D008422:Materials Testing; D010012:Osteogenesis / Q000187:drug effects*; D011817:Rabbits; D012886:Skull / Q000601:surgery*; D055114:X-Ray Microtomography
chemical_list: D002130:Calcium Phosphates; C485817:beta-tricalcium phosphate; D017886:Durapatite
keywords: animal experiments; biomaterials; bone substitutes; material sciences