Yuji Ishida1, Zuisei Kanno, Kunimichi Soma. 1. Orthodontic Science, Department of Orofacial Development and Function, Division of Oral Health Sciences, Graduate School, Tokyo Medical and Dental University, Tokyo, Japan. yjis.orts@tmd.ac.jp
Abstract
OBJECTIVE: To clarify the influence of occlusal hypofunction on the integrity of gingival tissue and gingival extracellular matrix biosynthesis. MATERIALS AND METHODS: Thirteen-week-old male Wistar rats were divided into two groups. To eliminate occlusal forces, all the right maxillary molars were extracted in the hypofunctional group. The control group was anesthetized but not subjected to surgery. The rats were killed at 2 and 4 weeks after the procedure, and the lower right second molars were prepared for histological analysis. To investigate the effect of occlusal hypofunction on collagen biosynthesis, the expression of connective tissue growth factor (CTGF) and lysyl oxidase (LOX) was determined by immunohistochemistry as well as histological examination by hematoxylin and eosin staining. RESULTS: Disorientation of the collagen fibers, proliferation of the connective tissue fibroblasts, and enlargement of epithelial intercellular gaps were observed in gingival tissue of rat molars with experimental occlusal hypofunction. Immunohistochemically, the expression of CTGF and LOX was increased significantly (P < .05) in the hypofunctional group. CONCLUSION: These results suggest that occlusal hypofunction can affect the structural integrity and the expression of CTGF and LOX in gingival tissue.
OBJECTIVE: To clarify the influence of occlusal hypofunction on the integrity of gingival tissue and gingival extracellular matrix biosynthesis. MATERIALS AND METHODS: Thirteen-week-old male Wistar rats were divided into two groups. To eliminate occlusal forces, all the right maxillary molars were extracted in the hypofunctional group. The control group was anesthetized but not subjected to surgery. The rats were killed at 2 and 4 weeks after the procedure, and the lower right second molars were prepared for histological analysis. To investigate the effect of occlusal hypofunction on collagen biosynthesis, the expression of connective tissue growth factor (CTGF) and lysyl oxidase (LOX) was determined by immunohistochemistry as well as histological examination by hematoxylin and eosin staining. RESULTS: Disorientation of the collagen fibers, proliferation of the connective tissue fibroblasts, and enlargement of epithelial intercellular gaps were observed in gingival tissue of rat molars with experimental occlusal hypofunction. Immunohistochemically, the expression of CTGF and LOX was increased significantly (P < .05) in the hypofunctional group. CONCLUSION: These results suggest that occlusal hypofunction can affect the structural integrity and the expression of CTGF and LOX in gingival tissue.