title: Effect of estrogen replacement and calcitonin therapies on bone around titanium implants placed in ovariectomized rats: a histometric study.
abstract: OBJECTIVE
  The aim of the present study was to evaluate whether hormone replacement therapy (HRT) and calcitonin (CT) administration could influence bone healing around implants placed in ovariectomized (OVX) rats.
  
  
  METHODS
  One screw-type titanium implant was placed bilaterally in OVX rats. The animals were assigned to one of the following groups: group 1 (n = 15), sham surgeries; group 2 (n = 15), OVX rats; group 3 (n = 14), OVX rats administered CT 4 days/week (16 IU/kg); group 4 (n = 14), OVX rats administered 17beta estradiol daily (20 microg/kg). After 60 days, the animals were sacrificed and undecalcified sections obtained. Bone-to-implant contact (BIC) and bone area (BA) around the implants were determined separately for the cortical (zone A) and cancellous (zone B) bone areas.
  
  
  RESULTS
  In zone A, intergroup analysis did not reveal a significant difference regarding BIC. In contrast, the HRT group (group 4) presented greater BA than groups 2 and 3 (P < .05). Data from zone B revealed that HRT eliminated the negative effect of the ovariectomy on BIC and BA (P < .05), while CT had no effect (P > .05).
  
  
  CONCLUSIONS
  It was the first study to evaluate and demonstrate the impact of HRT and CT on bone around titanium implants in an estrogen-deficient model.
  
  
  CONCLUSIONS
  Within the limits of the present study, it may be concluded that HRT may prevent the influence that estrogen deficiency exerts on bone healing around titanium implants.
authors.affiliation: Department of Prosthodontics and Periodontics, Division of Periodontics, School of Dentistry at Piracicaba, São Paulo, Brazil. nociti@fop.unicamp.br
authors.forename: Francisco Humberto
authors.initials: FH
authors.lastname: Nociti
authors.forename: Antonio Wilson
authors.initials: AW
authors.lastname: Sallum
authors.forename: Enilson Antonio
authors.initials: EA
authors.lastname: Sallum
authors.forename: Poliana Mendes
authors.initials: PM
authors.lastname: Duarte
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D001861:Bone Regeneration / Q000187:drug effects*; D002116:Calcitonin / Q000494:pharmacology*; D015921:Dental Implants; D004958:Estradiol / Q000494:pharmacology*; D015914:Estrogen Replacement Therapy; D004967:Estrogens / Q000172:deficiency*; D005260:Female; D020007:Implants, Experimental; D023421:Models, Animal; D016348:Osseointegration / Q000187:drug effects*; D010052:Ovariectomy; D010053:Ovary / Q000502:physiology*; D051381:Rats; D017208:Rats, Wistar; D018709:Statistics, Nonparametric; D013977:Tibia; D014025:Titanium; D014945:Wound Healing / Q000187:drug effects
chemical_list: D015921:Dental Implants; D004967:Estrogens; D004958:Estradiol; D002116:Calcitonin; D014025:Titanium