title: Effects of oestrogen deficiency and 17β-estradiol therapy on bone healing in calvarial critical size defects treated with bovine bone graft.
abstract: OBJECTIVE
  To histomorphometrically analyze the effect of ovariectomy-induced oestrogen deficiency and 17β-estradiol therapy on bone healing of surgically created critical-size defects (CSDs) treated with bovine bone graft (BBG).
  
  
  METHODS
  Forty-eight female rats were randomly assigned to the following 3 experimental groups (n=16): sham-operated animals (SHAM), ovariectomized animals (OVX) and ovariectomized animals treated with oestrogen (OVX+E2). OVX+E2 animals received daily subcutaneous injections of 17β-estradiol (20μg/kg) from 8 days after ovariectomy until euthanasia. Thirty days after the surgery, an 8mm CSD was surgically created in each calvaria of all animals and filled with BBG. Animals were euthanized at either 30 or 60 days postoperative. A histological analysis, percentage of Newly Formed Bone Area (NFBA), osteoblast and osteoclast number was histomorphometrically performed (p≤0.05).
  
  
  RESULTS
  At 30 days, SHAM group (8.82%±2.93) had significantly greater NFBA than OVX (4.66%±1.35) and OVX+E2 groups (5.85%±4.08) (p≤0.05). At 60 days, SHAM group (11.51%±3.08) and OVX+E2 group (9.84%±1.87) had significantly greater NFBA than OVX animals (5.12%±0.68) (p≤0.05). Fewer osteoblasts were observed in the OVX group at 30 (763.40±121.60) and 60 (696.60±80.92) days than in the SHAM group at 30 days (1356.00±95.38). Fewer osteoclasts were observed in the OVX+E2 group (3.25±2.16) than in the SHAM (9.75±1.82) and OVX (12.75±1.47) groups at 30 days (p≤0.05).
  
  
  CONCLUSIONS
  Oestrogen deficiency compromises bone healing in calvarial CSDs treated with BBG in ovariectomized rats. After 60 days post-surgery, 17β-estradiol therapy improved bone healing in calvarial CSDs treated with BBG in ovariectomized rats.
authors: Univ. Estadual Paulista - UNESP, Division of Periodontics, Department of Surgery and Integrated Clinic, Dental School of Araçatuba, Rua José Bonifácio, n° 1193, CEP: 16015-050, Araçatuba, São Paulo, Brazil. Electronic address: jumilanezi@hotmail.com.
authors: Juliano Milanezi
authors: JM
authors: de Almeida
authors: Univ. Estadual Paulista - UNESP, Division of Periodontics, Department of Surgery and Integrated Clinic, Dental School of Araçatuba, Rua José Bonifácio, n° 1193, CEP: 16015-050, Araçatuba, São Paulo, Brazil. Electronic address: afbosco@hotmail.com.
authors: Alvaro Francisco
authors: AF
authors: Bosco
authors: Univ. Estadual Paulista - UNESP, Division of Periodontics, Department of Surgery and Integrated Clinic, Dental School of Araçatuba, Rua José Bonifácio, n° 1193, CEP: 16015-050, Araçatuba, São Paulo, Brazil. Electronic address: paulal.faleiros@hotmail.com.
authors: Paula Lazilha
authors: PL
authors: Faleiros
authors: Univ. Estadual Paulista - UNESP, Division of Periodontics, Department of Surgery and Integrated Clinic, Dental School of Araçatuba, Rua José Bonifácio, n° 1193, CEP: 16015-050, Araçatuba, São Paulo, Brazil. Electronic address: drfabriziocabrera@hotmail.com.
authors: Victor Fabrizio Cabrera
authors: VF
authors: Pazmiño
authors: Univ. Estadual Paulista - UNESP, Division of Periodontics, Department of Surgery and Integrated Clinic, Dental School of Araçatuba, Rua José Bonifácio, n° 1193, CEP: 16015-050, Araçatuba, São Paulo, Brazil. Electronic address: a_murakawa@hotmail.com.
authors: Ana Cristina
authors: AC
authors: Murakawa
authors: Univ. Estadual Paulista - UNESP, Division of Periodontics, Department of Surgery and Integrated Clinic, Dental School of Araçatuba, Rua José Bonifácio, n° 1193, CEP: 16015-050, Araçatuba, São Paulo, Brazil. Electronic address: samarabonfante@uol.com.
authors: Samara
authors: S
authors: Bonfante
authors: Univ. Estadual Paulista - UNESP, Division of Periodontics, Department of Surgery and Integrated Clinic, Dental School of Araçatuba, Rua José Bonifácio, n° 1193, CEP: 16015-050, Araçatuba, São Paulo, Brazil. Electronic address: mjnagata@uol.com.br.
authors: Maria José Hitomi
authors: MJ
authors: Nagata
authors: Univ. Estadual Paulista - UNESP, Division of Periodontics, Department of Surgery and Integrated Clinic, Dental School of Araçatuba, Rua José Bonifácio, n° 1193, CEP: 16015-050, Araçatuba, São Paulo, Brazil; University Center of Educational Foundation of Barretos - UNIFEB, Department of Periodontics, Dental School of Barretos, Avenida Professor Roberto Frade Monte, n° 389, CEP: 14783-226, Barretos, São Paulo, Brazil. Electronic address: vg.garcia@uol.com.br.
authors: Valdir Gouveia
authors: VG
authors: Garcia
mesh_terms: D000818:Animals; D016025:Bone Transplantation; D002417:Cattle; D004958:Estradiol / Q000494:pharmacology*; D015914:Estrogen Replacement Therapy; D004967:Estrogens / Q000172:deficiency; D005260:Female; D010006:Osteoblasts / Q000187:drug effects; D010010:Osteoclasts / Q000187:drug effects; D010052:Ovariectomy; D051381:Rats; D012886:Skull / Q000601:surgery*; D014945:Wound Healing / Q000187:drug effects*
chemical_list: D004967:Estrogens; D004958:Estradiol
keywords: Bone grafting; Bone regeneration; Calvaria; Oestrogen replacement therapy