Effect of mastigatory hypofunction on mandibilar boné mass of Wistar rats ovarietomised or not / Efeito da hipofunção mastigatória na massa óssea da mandíbula de ratas Wistar submetidas ou não a ovariectomia

AUTOR(ES)
DATA DE PUBLICAÇÃO

2009

RESUMO

Objectives: 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 4 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 BMD (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 BMD (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 to hard-diet. Conclusions: Our results suggest that mandibular bone loss resulted from decreased mechanical loading during mastication, and was not affect by estrogen depletion

ASSUNTO(S)

osso e ossos/anatomia &histologia densitometry ratos wistar bite force densitometria mandíbula osteoporosis força da mordida osteoporose mandible ovariectomy wistar rats ovariectomia bone/anatomy &histology

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