Ovariectomy vs. hypofunction: their effects on rat mandibular bone.
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.
Rawlinson
S C F
SC
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.
Boyde
A
A
Davis
G R
GR
Howell
P G T
PG
Hughes
F J
FJ
Kingsmill
V J
VJ
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
D004967:Estrogens