Effect of mastication on mandibular growth

Research Project

Project/Area Number	20890223
Research Category	Grant-in-Aid for Young Scientists (Start-up)
Allocation Type	Single-year Grants
Research Field	Orthodontic/Pediatric dentistry
Research Institution	Showa University
Principal Investigator	ENOMOTO Akiko Showa University, 歯科矯正学教室, 普通研究生 (60514982)
Project Period (FY)	2008 – 2009
Project Status	Completed (Fiscal Year 2009)
Budget Amount *help	¥3,302,000 (Direct Cost: ¥2,540,000、Indirect Cost: ¥762,000) Fiscal Year 2009: ¥1,560,000 (Direct Cost: ¥1,200,000、Indirect Cost: ¥360,000) Fiscal Year 2008: ¥1,742,000 (Direct Cost: ¥1,340,000、Indirect Cost: ¥402,000)
Keywords	成長発育 / 形態計測 / 下顎頭軟骨 / 咀嚼 / Μct / μCT
Research Abstract	The aim of this investigation was to ascertain whether changes in mastication influence on mandibular growth. Three-week-old male ICR mice were assigned to the following three diet groups : mice fed a hard diet (HD group) ; mice fed a soft diet (SD group) ; and mice alternately fed hard and soft diets (HSD group). The mandibular condylar cartilage was evaluated histologically by hematoxylin and eosin staining. Chondrocyte proliferative ability was evaluated by immunostaining of proliferating cell nuclear antigen (PCNA). For the observation of changes in gene expression of osteopontin and type X collagen, the mandibular condylar cartilage was selectively collected and expressions of genes related to cartilaginous growth were quantitatively evaluated by real-time PCR and immunostaining. And we investigated how the shape of the mandible in mice is affected by food hardness using micro computed tomography (μCT).