Effect of estrogen replacement and calcitonin therapies on bone around titanium implants placed in ovariectomized rats: a histometric study.
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.
Nociti
Francisco Humberto
FH
Department of Prosthodontics and Periodontics, Division of Periodontics, School of Dentistry at Piracicaba, São Paulo, Brazil. nociti@fop.unicamp.br
Sallum
Antonio Wilson
AW
Sallum
Enilson Antonio
EA
Duarte
Poliana Mendes
PM
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
D015921:Dental Implants; D004967:Estrogens; D004958:Estradiol; D002116:Calcitonin; D014025:Titanium