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

Department of Periodontics, Dental Research Division, Guarulhos University, Guarulhos, São Paulo, Brazil.
Journal of Periodontology (Impact Factor: 2.57). 08/2012; DOI: 10.1902/jop.2012.120192
Source: PubMed

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.

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    ABSTRACT: SCOPE: Caffeine, a methylxanthine present in coffee, has been postulated to be responsible for an increased risk of osteoporosis in coffee drinkers; however, the data are inconsistent. The aim of the present study was to investigate the effects of a moderate dose of caffeine on the skeletal system of rats with normal and decreased estrogen level (developing osteoporosis due to estrogen deficiency). METHODS AND RESULTS: The experiments were carried out on mature nonovariectomized and ovariectomized Wistar rats, divided into control rats and rats receiving caffeine once daily, 20 mg/kg p.o., for 4 wk. Serum bone turnover markers, bone mass, mass of bone mineral, calcium and phosphorus content, histomorphometric parameters, and bone mechanical properties were examined. Caffeine favorably affected the skeletal system of ovariectomized rats, slightly inhibiting the development of bone changes induced by estrogen deficiency (increasing bone mineralization, and improving the strength and structure of cancellous bone). Moreover, it favorably affected mechanical properties of compact bone. There were no significant effects of caffeine in rats with normal estrogen levels. CONCLUSION: In conclusion, results of the present study indicate that low-to-moderate caffeine intake may exert some beneficial effects on the skeletal system of mature organisms.
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