Effect of Aging and Teeth Loss on Mastication SAMP8

Objectives: According to animal experiments, it is recently said that loss of teeth has various influence on the whole body and the central function. The masticatory ability and learning and memory ability due to loss of maxillary molar teeth has been demonstrated by using SAMP8 (Senescence-Accelerated Mouse P8). In this report, the influence resulting from the difference of location of the molar teeth exerted on the masticatory ability is studied based on age-related change.

Methods: SAMP8 at the age of 2 months were divided into 8 groups in total. The 2 untreated groups were raised until 3, 8 months of age, and the remaining groups, with left maxillary molar teeth, maxillary molar teeth of both sides, and maxillary and mandiblar molar teeth on both sides were extracted at the age of 2 months, and raised until 3, 8 months of age as well. SAMP8 had the stomach contents extracted, after ingesting the examination feed freely. And the masticatory ability of SAMP8 was evaluated by making the pulverization condition of content into particle size distribution.

Results: A significant impairment of masticatory ability due to aging was confirmed in the untreated groups (P<0.05, Mann-Whitney U test). Compared with the untreated groups, the masticatory ability of the groups which had the maxillary molar teeth on both sides and the maxillary and mandiblar molar teeth extracted decreased significantly (P<0.05, Scheffe test).

Conclusions: In SAMP8, it became clear that the impairment of masticatory ability was caused by aging and molar teeth loss. Moreover, compared with the untreated groups, the impairment of masticatory ability of the groups which had the maxillary molar teeth on both sides and the maxillary and mandiblar molar teeth extracted decreased and its condition continued.