A Histopathological and Immunohistochemical Study on the Effects of the Resin Fragments of the Abutment Construction in the Periodontal Tissues in Healthy (m+/m+) and Diabetic Model Mice (db/db)

The materials of high molecular compounds have been widely used in the field of dental clinics. Although preparation of the tooth abutment and contamination of the metal fragments are known to cause the discoloration and injury in the periodontal tissues in the field of crown and bridge prosthodontic clinics, the changes by the precipitation of composite resin fragments have not been fully clarified, yet. In addition, diabetes mellitus has recently been increased because of an advanced age, life style and conditions, and also, the patients with diabetes have increased in dental clinics. Therefore, the present study was undertaken the histopathological, histochemical and immunohistochemical analyses, in order to elucidate the changes of the periodontal tissues by injecting the composite resin fragments. The histopathological reactions of the periodontal tissues in both healthy (m+/m+) and diabetic (db/db) mice were also compared. Histopathologically, neutrophil infiltration was remarkably observed around the fragments of the composite resin at 3 days after the injection, and then, the formation of the granulation tissues with appearance of macrophages (foamy cells) at 7 and 14 days in m+/m+. Multinuclear giant cells were also observed at 14 days in m+/m+. In db/db, neutrophil infiltration was not so remarkable at 3 days, and relatively increase of the infiltration was observed at 7 days, and formation of the granulation tissues with appearance of the foamy cells at 14 days. The numbers of the mast cells, indicated metachromasia with toluidine blue pH 2.5 staining, peaked at 3 days and then decreased at 7 and 14 days in m+/m+, whereas the peak of the mast cells was at 7 days in db/db. Immunohistochemically, the peak cell rate of CD68-positive macrophage was found at 3 days after the injection, and the rate decreased at 7 and 14 days in m+/m+, whereas the rate gradually increased and showed the peak at 14 days after the injection in db/db. The peak of the cell rate of matrix metalloproteinase-2-positive macrophage was observed at 3 days, and the rates tended to gradually decrease at 7 and 14 days after the injection in m+/m+, whereas lower cell rate without peak point was recognized at each day in db/db. These results suggested that db/db showed delay of the process of biological reactions for the foreign bodies of the composite resin fragments compared to m+/m+. Furthermore, the delay of the reaction depended on the inhibition for the fibrosis accelerated by macrophages and mast cells.