title: Influence of ovariectomy and masticatory hypofunction on mandibular bone remodeling.
abstract: BACKGROUND
  This study was designed to examine the effect of masticatory hypofunction and estrogen deficiency on mandible bone mass and compare this site with spine and femoral bone.
  
  
  METHODS
  Twenty-four rats were ovariectomized (OVX) or Sham-operated (Sham) and analyzed after feeding with hard diet (Hard) or soft diet (Soft). They were divided into four groups: (GI)Sham-Hard; (GII)OVX-Hard; (GIII)Sham-Soft and (GIV)OVX-Soft. Bone mineral density (BMD) was measured in the spine and femur in the baseline and at the end of the study, and DeltaBMD (final BMD - baseline BMD) was calculated. In mandible bone, BMD and histomorphometry were analyzed at the end of the experiment.
  
  
  RESULTS
  Sham rats showed higher spine (GI: 13.5%vs GII: 0.74%, P < 0.01; GIII: 10.67%vs GIV: -4.36%, P < 0.001) and femur DeltaBMD (GI: 14.43%vs GII: 4.42%, P < 0.01; GIII: 10.58%vs GIV: 0.49%, P < 0.001) than OVX, but no difference was observed in mandible BMD among these groups (P > 0.05). Soft-diet groups showed decreased mandible BMD compared with hard-diet groups (GIV vs GII, P < 0.01; GIII vs GI, P < 0.01). Similarly, mandibular condyle histomorphometry showed that soft-diet groups presented a significant decrease in trabecular thickness and volume (GIV vs GII, P < 0.05; GIII vs GI, P < 0.01) compared with hard diet.
  
  
  CONCLUSIONS
  Our results suggest that mandibular bone loss resulted from decreased of mechanical loading during mastication, and was not affect by estrogen depletion.
authors.affiliation: Bone Metabolism Laboratory of Rheumatology Division, Universidade de São Paulo, Sao Paulo 01246-903, Brazil.
authors.forename: I M F
authors.initials: IM
authors.lastname: Patullo
authors.forename: L
authors.initials: L
authors.lastname: Takayama
authors.forename: R F
authors.initials: RF
authors.lastname: Patullo
authors.forename: V
authors.initials: V
authors.lastname: Jorgetti
authors.forename: R M R
authors.initials: RM
authors.lastname: Pereira
mesh_terms: D000821:Animal Feed; D000818:Animals; D001732:Bite Force; D015519:Bone Density / Q000502:physiology*; D004195:Disease Models, Animal; D004967:Estrogens / Q000172:deficiency* / Q000502:physiology; D005260:Female; D005269:Femur / Q000033:anatomy & histology / Q000502:physiology; D006801:Humans; D008334:Mandible / Q000033:anatomy & histology / Q000502:physiology; D008336:Mandibular Diseases / Q000150:complications / Q000209:etiology* / Q000503:physiopathology; D008409:Mastication / Q000502:physiology; D015663:Osteoporosis, Postmenopausal / Q000150:complications / Q000209:etiology* / Q000503:physiopathology; D010052:Ovariectomy; D051381:Rats; D017208:Rats, Wistar; D013131:Spine / Q000033:anatomy & histology / Q000502:physiology; D018709:Statistics, Nonparametric; D013314:Stress, Mechanical
chemical_list: D004967:Estrogens