Effects of Estrogen Deficiency and/or Caffeine Intake on Alveolar Bone Loss, Density and Healing: A Study in Rats.

Abstract

Background: To evaluate the effects of caffeine and/or estrogen deficiency on ligature-induced bone loss (BL), trabecular bone area (TBA) and post-extraction bone healing (BH). Methods: Rats were assigned into one of the groups: Control: non-ingestion of caffeine/sham-surgery (n=15); Caffeine: ingestion of caffeine/sham-surgery (n=15); Ovariectomized (OVX): non-ingestion of caffeine/ovariectomy (n=15); Caffeine/OVX: ingestion of caffeine/ovariectomy. The rats were under caffeine administration during 65 days and/or estrogen deficiency for 51 days. On the 21(st) day after ovariectomy, one first mandibular molar received a ligature while the contralateral tooth was left unligated. The first maxillary molars were extracted at 8 days before sacrifice. BL, TBA, the positive cells for tartrate-resistant acid phosphatase (TRAP), receptor activator of NF-(К)B ligand (RANKL) and osteoprotegerin (OPG) were analyzed in the furcation area of mandibular molars. Histometric BH and gene expression of bone morphogenetic protein (BMP)-2, BMP-7, osteopontin and bone sialoprotein were evaluated in alveolar sockets. Results: The caffeine group presented the greatest BL and the OVX group the highest number of TRAP+ cells around ligated teeth (p<0.05). The control group presented higher TBA and BH than the other groups (p<0.05). All test groups presented higher RANKL/OPG+ cells than the control group around ligated/unligated teeth. The OVX and caffeine/OVX groups presented greater number of TRAP+ cells around unligated teeth than the control group (p<0.05). There were no differences among groups for gene expression (p>0.05). Conclusions: Caffeine increased BL in the presence of ligature. Caffeine and/or estrogen deficiency decreased TBA in absence of ligature and reduced BH after tooth extraction.