title: Slow resorption of anorganic bovine bone by osteoclasts in maxillary sinus augmentation.
abstract: OBJECTIVE
  Different biomaterials have been suggested for guided bone regeneration (GBR). These might show the ideal properties to let a new bone formation in the grafted area. Among these ideal features, it is essential their controlled resorption in order to be replaced for new vital bone. Bovine bone has been used widely as a good biomaterial for GBR, however there is still an interesting controversy about its resorbable capacity. In this sense, the objective of this study was to examine the behavior of anorganic bovine bone (ABB) in long-term maxillary sinus graft healing and study its relationship with morphological and morphometrical variables.
  
  
  METHODS
  Seventeen maxillary sinus augmentation procedures were performed in patients. Bone cores were obtained from implant receptor sites at 6 months, 3 years, and 7 years of implant placement for histological, morphometric, and immunohistochemical (tartrate resistant acid phosphatase [TRAP]/cathepsin K/CD68) studies.
  
  
  RESULTS
  The percentages of bone, ABB particles, connective tissue, osteocytes, and osteoblasts in maxillary sinus grafts were similar at 6 months, 3 years, and 7 years. A progressive and significant decrease was detected in osteoclasts (p = .05, Kruskal-Wallis test), TRAP and cathepsin K expression (p = .014 and p = .021, respectively), and osteoid lines (p = .038).
  
  
  CONCLUSIONS
  According to these data, a decrease in osteoclasts over time may, partially, explain the ABB persistence observed in core biopsies. Further studies with more cases and different graft maturation times are required to elucidate the resorption rates and cell events underlying these phenomena.
authors.affiliation: Associate professor, Oral Surgery and Implant Dentistry Department, School of Dentistry, University of Granada, Granada, Spain; visiting associate professor, Department of Periodontics and Oral Medicine School of Dentistry, University of Michigan, Ann Arbor, MI, USA associate professor, Traumatology and Orthopedic Surgery Department, "San Cecilio" Clinical Hospital and University of Granada, Granada, Spain associate professor, Periodontology Department, School of Dentistry, University of Granada, Granada, Spain professor and chairman, Periodontology Department, School of Dentistry, University of Buenos Aires, Buenos Aires, Argentina professor, Department of Maxillofacial Surgery, Lithuanian University of Health Sciences, Kaunas, Lithuania associate professor, Pathology Department, School of Medicine, and IBIMER, University of Granada, Granada, Spain.
authors.forename: Pablo
authors.initials: P
authors.lastname: Galindo-Moreno
authors.forename: Pedro
authors.initials: P
authors.lastname: Hernández-Cortés
authors.forename: Francisco
authors.initials: F
authors.lastname: Mesa
authors.forename: Nelson
authors.initials: N
authors.lastname: Carranza
authors.forename: Gintaras
authors.initials: G
authors.lastname: Juodzbalys
authors.forename: Mariano
authors.initials: M
authors.lastname: Aguilar
authors.forename: Francisco
authors.initials: F
authors.lastname: O'Valle
mesh_terms: D000328:Adult; D000818:Animals; D001862:Bone Resorption; D002417:Cattle; D006801:Humans; D008875:Middle Aged; D010010:Osteoclasts / Q000166:cytology*; D059546:Sinus Floor Augmentation