title: Effects of estrogen deficiency and/or caffeine intake on alveolar bone loss, density, and healing: a study in rats.
abstract: BACKGROUND
  The aim of this study is to evaluate the effects of caffeine and/or estrogen deficiency on ligature-induced bone loss (BL), trabecular bone area (TBA), and postextraction bone healing (BH).
  
  
  METHODS
  Rats were assigned into one of the following groups (15 each): 1) control = non-ingestion of caffeine/sham surgery; 2) caffeine = ingestion of caffeine/sham surgery); 3) ovariectomized (OVX) = non-ingestion of caffeine/ovariectomy; or 4) caffeine/OVX = ingestion of caffeine/ovariectomy. The rats were under caffeine administration for 65 days and/or estrogen deficiency for 51 days. On day 21 after ovariectomy, one first mandibular molar received a ligature and the contralateral tooth was not ligated. The first maxillary molars were extracted 8 days before sacrifice. BL, TBA, the positive cells for tartrate-resistant acid phosphatase (TRAP), receptor activator of nuclear factor-κB 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-positive (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 a 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 ligated teeth. Caffeine and/or estrogen deficiency decreased TBA in the unligated teeth and reduced BH after tooth extraction.
authors.affiliation: Department of Periodontics, Dental Research Division, Guarulhos University, Guarulhos, São Paulo, Brazil.
authors.forename: Joyce Pinho
authors.initials: JP
authors.lastname: Bezerra
authors.forename: Ariane
authors.initials: A
authors.lastname: de Siqueira
authors.forename: Amanda Gonçalves
authors.initials: AG
authors.lastname: Pires
authors.forename: Marcelo Rocha
authors.initials: MR
authors.lastname: Marques
authors.forename: Poliana Mendes
authors.initials: PM
authors.lastname: Duarte
authors.forename: Marta Ferreira
authors.initials: MF
authors.lastname: Bastos
mesh_terms: D000135:Acid Phosphatase / Q000032:analysis; D016301:Alveolar Bone Loss / Q000209:etiology*; D000818:Animals; D015415:Biomarkers / Q000032:analysis; D015519:Bone Density / Q000187:drug effects*; D055396:Bone Morphogenetic Protein 2 / Q000032:analysis; D055419:Bone Morphogenetic Protein 7 / Q000032:analysis; D002110:Caffeine / Q000494:pharmacology*; D000697:Central Nervous System Stimulants / Q000494:pharmacology*; D004967:Estrogens / Q000172:deficiency*; D005260:Female; D058574:Integrin-Binding Sialoprotein / Q000032:analysis; D007527:Isoenzymes / Q000032:analysis; D008334:Mandible / Q000187:drug effects / Q000473:pathology; D008437:Maxilla / Q000187:drug effects / Q000473:pathology; D008963:Molar / Q000473:pathology / Q000601:surgery; D053495:Osteopontin / Q000032:analysis; D053244:Osteoprotegerin / Q000032:analysis; D010052:Ovariectomy; D053245:RANK Ligand / Q000032:analysis; D051381:Rats; D017208:Rats, Wistar; D000071681:Tartrate-Resistant Acid Phosphatase; D014081:Tooth Extraction; D020390:Tooth Socket / Q000187:drug effects / Q000473:pathology; D014945:Wound Healing / Q000187:drug effects
chemical_list: D015415:Biomarkers; C525720:Bmp2 protein, rat; C525821:Bmp7 protein, rat; D055396:Bone Morphogenetic Protein 2; D055419:Bone Morphogenetic Protein 7; D000697:Central Nervous System Stimulants; D004967:Estrogens; C546873:Ibsp protein, rat; D058574:Integrin-Binding Sialoprotein; D007527:Isoenzymes; D053244:Osteoprotegerin; D053245:RANK Ligand; C506897:Spp1 protein, rat; C506032:Tnfrsf11b protein, rat; D053495:Osteopontin; D002110:Caffeine; D000135:Acid Phosphatase; D000071681:Tartrate-Resistant Acid Phosphatase