title: In vivo evaluation of shark teeth-derived bioapatites.
abstract: OBJECTIVE
  The present work proposes the shark teeth as a new source of bioapatites for bone filler applications in maxillary sinus elevation, periodontal regeneration or implants placement. This abundant fishing by-product provides an improved hydroxyapatite (HA) with fluorine contributions. The in vivo evaluation of osteointegration and bone mineral density levels promoted by these marine bioapatites was the main objective.
  
  
  METHODS
  Marine bioapatite granules of two sizes (1 mm, <20 μm) were obtained and characterized (XRD, SEM, ICP-OES) to determine morphology and composition. In vivo evaluation was performed, after bioapatites implantation in critical defects of parietal bone of 25 rats, for 3 weeks. Commercial synthetic HA/βTCP (60/40%) material and unfilled defects were used as controls. Radiology, micro-CT, histology and quantification of bone mineral density are presented.
  
  
  RESULTS
  These marine bioapatites presented a globular porous morphology. A biphasic composition ~70% apatitic (HA, apatite-CaF, fluorapatite) and ~30% non-apatitic phase (whitlockite, tricalcium bis(orthophosphate)), with contributions of F (1.0 ± 0.5%wt), Na (0.9 ± 0.2%wt) and Mg (0.65 ± 0.04%wt) was confirmed. After implantation period, higher osteointegration of 1-mm marine bioapatites than commercial synthetic granules was observed, together with bone formation from the defect surroundings but also at central area (potential osteoinductive properties). New bone cells penetrated inside pores and inter-granular cavities. Higher bone mineral density, in both 1-mm and <20-μm granules, than on commercial synthetic graft was determined, being significant in 1-mm bioapatites (a P < 0.05).
  
  
  CONCLUSIONS
  Shark teeth bioapatites were successfully validated as new functionally efficient bone filler in rat model, promoting significantly increased bone mineral density than synthetic control.
authors: New Materials Group, Applied Physics Department, Institute of Biomedical Research (IBI), University of Vigo, Vigo, Spain.
authors: Miriam
authors: M
authors: López-Álvarez
authors: Laboratory of Endocrinology, Department of Functional Biology and Health Sciences, Center for Biomedical Research CINBIO, University of Vigo, Vigo, Spain.
authors: Eva
authors: E
authors: Vigo
authors: New Materials Group, Applied Physics Department, Institute of Biomedical Research (IBI), University of Vigo, Vigo, Spain.
authors: Cosme
authors: C
authors: Rodríguez-Valencia
authors: Laboratory of Endocrinology, Department of Functional Biology and Health Sciences, Center for Biomedical Research CINBIO, University of Vigo, Vigo, Spain.
authors: Verónica
authors: V
authors: Outeiriño-Iglesias
authors: New Materials Group, Applied Physics Department, Institute of Biomedical Research (IBI), University of Vigo, Vigo, Spain.
authors: Pío
authors: P
authors: González
authors: New Materials Group, Applied Physics Department, Institute of Biomedical Research (IBI), University of Vigo, Vigo, Spain.
authors: Julia
authors: J
authors: Serra
mesh_terms: D000818:Animals; D001031:Apatites / Q000302:isolation & purification; D018786:Bone Substitutes / Q000302:isolation & purification; D017886:Durapatite / Q000302:isolation & purification; D051381:Rats; D017207:Rats, Sprague-Dawley; D012754:Sharks; D014070:Tooth / Q000737:chemistry
chemical_list: D001031:Apatites; D018786:Bone Substitutes; D017886:Durapatite; C025105:fluorapatite
keywords: animal experiments; biomaterials; bone regeneration; bone substitutes; guided tissue regeneration