Comparative Study on Effects of Silver and Resin Fragments Injected into Periodontal Tissues in Healthy (m + /m +) and Diabetic Model (db/db) Mice with Special Reference to Histopathological and Immunohistochemical Observation

Abstract

High molecular weight compounds have been widely used in the field of dentistry. Although preparation of the tooth abutment and contamination by metal fragments are known to cause discoloration and injury in the periodontal tissues in the field of crown and bridge prosthodontics, the changes due to metal and composite resin fragments have not been fully comparatively studied and clarified to date.
In addition, as patients with diabetes are more frequently encountered in dental clinics, the present study conducted histopathological, histochemical and immunohistochemical analyses in order to comparatively elucidate the changes in periodontal tissues after injection of metal（silver group）or composite resin fragments（resin group）. The histopathological reactions of the periodontal tissues in both healthy（m+/m+）and diabetic（db/db）mice were also compared at 28 days after injection.
Histopathologically and immunohistochemically, inflammatory cell infiltration and CD68- and MMP-2-positive macrophages were observed around the silver and resin fragments,and the fragments were decreased during fibrosis up to 28 days; these findings were more marked in the resin group than in the silver group. In addition, accumulation of the macrophages and subsequent fibrosis showed a delay in db/db. Furthermore, the number of mast cells was higher degree in the resin group than in the silver group, and was higher in db/db than in m+/m+, indicating that resin induces an allergic reaction in db/db.
These results suggest that resin fragments are more readily excised than silver fragments due to the higher level of phagocytosis and antigen-presenting activity of macrophages. Furthermore, critical changes against precipitation were delayed in db/db as compared to m+m+.