Effects of masticatory hypofunction on mandibular morphology, mineral density and basal bone area|
da Silva Guerreiro, Fernanda; Diniz, Péricles; Carvalho, Paulo Eduardo Guedes; Ferreira, Eduardo Cargnin; Avancini, Sandra Regina Paulon & Ferreira-Santos, Rívea Inês
Aim: This experimental study investigated the association between masticatory hypofunction
and mandibular morphological dimensions and internal bone characteristics.
21-day-old male Wistar rats were randomly divided into two groups, according to the diet
consistency. The control group (CG) was fed a solid diet (pellets) and the experimental group
(EG) received a powdered diet during 50 days. All animals were euthanized and their mandibles
removed and processed for histomorphometric analysis. A calibrated examiner performed linear
and angular measurements (mandibular body length and height, mandibular lengths, ramus
depth and height, mandibular base depth, mandibular head and gonial angle) on photographs,
estimated bone density in the mandibular ramus region on digital radiographs and assessed the
area of cortical and trabecular bone tissue in the second molar region, in 5-μm-thick serial cuts
stained with Cason’s Trichrome. Measurements for the study groups were compared using
Mann-Whitney test (α=0.05).
Results: some of the macroscopic dimensions evaluated on
photographs were significantly smaller in EG compared to CG, specifically mandibular ramus
height (10.77 mm vs. 11.11 mm, p=0.0375), mandibular body length (21.67 mm vs. 22.36 mm,
p=0.0165) and height (4.24 mm vs. 4.54 mm, p=0.0016), as well as mandibular base depth
(1.24 mm vs. 1.47 mm, p=0.0325). The relative mineral bone density was significantly decreased
in EG (1.04) compared to CG (1.25), p<0.001. Rats in the EG also presented smaller trabecular
and cortical bone area (2.36 mm²) than those in CG (3.16 mm²), p<0.001.
Based on the above-mentioned measurements, it may be concluded that masticatory hypofunction
induced by a powdered diet affected mandibular morphology and was associated with significantly
reduced bone content.
mastication; diet; mandible; bone development