Effects of masticatory hypofunction on mandibular morphology, mineral density and basal bone area

Abstract

Aim: This experimental study investigated the association between masticatory hypofunction and mandibular morphological dimensions and internal bone characteristics. Methods: Twentyfour 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. Conclusions: 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.

FGF signaling patterns cell fate at the interface between tendon and bone

“…Isosurface renderings with equal threshold were measured using the 3D measuring tool. All jaw measurements and landmarks were measured as previously described (Guerreiro et al, 2013). These experiments were performed on at least three biological replicates, which we defined as three same-sex littermate pairs (control and mutant) derived from three different litters.…”

The impact of dietary consistency on structural craniofacial components: Temporomandibular joint/condyle, condylar cartilage, alveolar bone and periodontal ligament. A systematic review and meta-analysis in experimental in vivo research

“…In 15 studies (Abed, Buschang, Taylor, & Hinton, 2007;Bresin, Kiliaridis, & Strid, 1999;Endo, Mizutani, Yasue, Senga, & Ueda, 1998;Enomoto et al, 2014;Enomoto et al, 2010;Guerreiro et al, 2013;Hichijo et al, 2014;Hinton & Carlson, 1986;Ikeda, Yonemitsu, Takei, Shibata, & Ono, 2014;Kingsmill, Boyde, Davis, Howell, & Rawlinson, 2010;Maki, Nishioka, Shioiri, Takahashi, & Kimura, 2002;McFadden, McFadden, & Precious, 1986;Shimizu et al, 2013;Tanaka et al, 2007;Vaid, Pradhan, & Chakrabarti, 2002), the animals were randomly allocated to either hard or soft diet feeding group, although no details of the randomization procedure were reported. In the rest (n= 18) of the studies (Barber, Green, & Cox, 1963;Beecher & Corruccini, 1981a;Bouvier, 1988;Bouvier & Hylander, 1984;Bouvier & Zimny, 1987;Bresin, Johansson, & Kiliaridis, 1994;Bresin, Kiliaridis, & Strid, 1999;Ito, Mitani, & Kim, 1988;Kiliaridis, Bresin, Holm, & Strid, 1996;Mavropoulos, Odman, Ammann, & Kiliaridis, 2010;Odman, Mavropoulos, & Kiliaridis, 2008;Orajarvi, 2015;Orajarvi et al, 2011;Orajarvi et al, 2012;Stahl & Dreizen, 1964;Watt & Williams, 1951;Yamada & Kimmel, 1991) no obvious randomization was done or allocation was implemented by convenience.…”

“…States (Abed et al, 2007;Barber et al, 1963;Beecher & Corruccini, 1981a;Bouvier, 1988;Bouvier & Zimny, 1987;Hinton & Carlson, 1986;Stahl & Dreizen, 1964), Finland (Orajarvi, 2015;Orajarvi et al, 2011;Orajarvi et al, 2012;Tiilikainen et al, 2011), Sweden (Bresin, Johansson, & Kiliaridis, 1994;Bresin, Kiliaridis, & Strid, 1999;Kiliaridis et al, 1996;Odman et al, 2008), Canada (McFadden et al, 1986Watt & Williams, 1951), Switzerland (Kiliaridis, Thilander, Kjellberg, Topouzelis, & Zafiriadis, 1999;Mavropoulos et al, 2010), Brazil (Guerreiro et al, 2013), India (Vaid et al, 2002), Puerto Rico (Bouvier & Hylander, 1984) and United Kingdom (Kingsmill et al, 2010). In the subgroup of studies dealing with temporomandibular joint/condyle of rats (Barber et al, 1963;Beecher & Corruccini, 1981a;Bouvier, 1988;Bouvier & Hylander, 1984;Bouvier & Zimny, 1987;Bresin, Kiliaridis, & Strid, 1999;Endo et al, 1998;Guerreiro et al, 2013;Hinton & Carlson, 1986;Ikeda et al, 2014;Kiliaridis et al, 1996;Kiliaridis et al, 1999;Maki et al, 2002;McFadden et al, 1986;Odm...…”

A distal 594bp ECR specifies Hmx1 expression in pinna and lateral facial morphogenesis and is regulated by Hox-Pbx-Meis

“…The paraoccipital processes, which are functionally analogous to the mastoid process in humans, are points of attachment of some of the major muscles of mastication and lateral head movement. Given that it is well established that mechanical strain forces from mastication can affect development of the bony mandibular angular process and patency of the cranial sutures (de Jong et al, 2011;Guerreiro et al, 2013;Rafferty et al, 2007), the altered shape of the mandibular angle and premature closure of the temporal sutures in dumbo mice are likely to be secondary to decreased biomechanical function. Additionally, we confirm here that dumbo mice exhibit nerve branching and organization defects of some lateral sensory facial nerves that innervate the pinnae and surrounding tissue, extending our prior findings (Quina et al, 2012b).…”