Experimental Model of Occlusal Trauma in Mouse Periodontal Tissues

Abstract

The aim of this study was to establish a model, which can be used to investigate the response of periodontal tissues to excessive occlusal loading in mice by observing histopathological changes. The experiment was performed on ten 7-week-old ddY male mice. Under general anesthesia by intraperitoneal injection pentobarbital sodium, a micro-plus-screwpin (head part, 1.7mm in diameter, thickness 0.5mm thickness) was screwed into the pulp cavity of the upper-left-first molar. R_mCT images of the experimental site indicated the occlusal contact position between the upper-and lower-left-first molars during the experimental periods. A micro-plus-screwpin was maintained at a constant position on the occlusal surface throughout the experimental period. Histopathological changes of the periodontal ligament at the furcation lesion of the lower-left-first molar and its surrounding periodontal tissues were observed under a light microscope. The densities of deeply dyeing cells in hematoxylin staining with a round-shaped nucleus were increased in the periodontal ligament, with a peak effect of day 4. Multinucleated giant cells appeared in the central lesion of the periodontal ligament on day 7. The distribution of resorption on the surface of both of the cementum and the alveolar bone was accompanied by multinucleated giant cells, which expanded rapidly from day 7 to day 14. These results showed that histopathological changes of periodontal tissues to excessive occlusal load were observed at the furcation area of molar teeth. The present method confirmed the effectiveness of the experimental model to examine the occlusal trauma on periodontal tissues produced by excessive occlusal load.

Cytological Kinetics of Periodontal Ligament in an Experimental Occlusal Trauma Model

“…The occlusal surface of the upper left first molar was raised by the 0.5 mm thickness of the head of the micro-plus-screwpin (Fig. 1 ) 23 .…”

“…R_mCT was used to confirm the occlusal contact between upper left first molar and lower left first molar 23 . At 4, 7, and 14 days after increasing occlusal height, the mice were sacrificed by an overdose of pentobarbital sodium.…”

“…These research reports failed to performed sufficient validation on the cytological kinetics of the periodontal tissues in the case of occlusal trauma. In the view of establishing an animal experimental system that is highly versatile and repeatable, we built an experimental system in which overload is added to the molar region of mice, and we reexamined the periodontal tissues from the viewpoint of cytological kinetics 23 . We then performed histopathological and also immunohistochemical examinations.…”

Bone Marrow Mesenchymal Cell Contribution in Maintenance of Periodontal Ligament Homeostasis

“…The experimental model diagram is shown in Figure 3. Periodontal connective tissue remodeling occurred due to traumatic occlusal overload [31]. In the remodeling course, the fibroblasts act as an important role.…”

“…HSP 27 and HSP 70 have detailed observation results on damaged periodontal tissue by Muraoka et al [5][6][7]. Based on the experiments of Fujii et al [31] and Takaya et al [32], we carried out the IHC study on the histopathological changes of mouse dental tissue and on HSP.…”