title: Ovariectomy vs. hypofunction: their effects on rat mandibular bone.
abstract: Previous studies have suggested that the mandible may be more influenced by mechanical loading than by circulating hormone levels. We tested the hypothesis that hypofunction has a greater influence than ovariectomy on mandibular bone. Two-month-old rats were ovariectomized (OVX) or had maxillary molars removed from one side to induce unilateral mandibular hypofunction. Control animals remained untreated. After 5 months, animals were killed, and bones were assessed by micro-tomography (muCT), quantitative back-scattered electron analysis in an SEM (qBSE-SEM), and light microscopy. Mineralization density was reduced in calvarial, maxillary, and mandibular alveolar bone following OVX, yet was increased in lingual mandibular alveolar bone of the hypo-function animals compared with controls. OVX caused a reduction in osteocyte density in alveolar bone, while hypofunction showed an increase compared with controls. Hypofunction led to alveolar bone becoming more highly mineralized and more cellular, while ovariectomy caused a reduction in both mineralization density and osteocyte numbers.
authors.affiliation: Centre for Adult Oral Health, Institute of Dentistry, Queen Mary University of London, Barts, and The London School of Medicine & Dentistry, Turner Street, Whitechapel, London E1 2AD, UK.
authors.forename: S C F
authors.initials: SC
authors.lastname: Rawlinson
authors.forename: A
authors.initials: A
authors.lastname: Boyde
authors.forename: G R
authors.initials: GR
authors.lastname: Davis
authors.forename: P G T
authors.initials: PG
authors.lastname: Howell
authors.forename: F J
authors.initials: FJ
authors.lastname: Hughes
authors.forename: V J
authors.initials: VJ
authors.lastname: Kingsmill
mesh_terms: D000539:Alveolar Process / Q000166:cytology*; D000818:Animals; D015519:Bone Density; D002113:Calcification, Physiologic / Q000502:physiology; D002467:Cell Nucleus; D055032:Electron Microscope Tomography; D004967:Estrogens / Q000172:deficiency; D005260:Female; D008334:Mandible / Q000503:physiopathology*; D008964:Molar, Third / Q000601:surgery; D010024:Osteoporosis / Q000209:etiology*; D010052:Ovariectomy; D010053:Ovary / Q000502:physiology*; D016062:Porosity; D011897:Random Allocation; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D004967:Estrogens