Abstract
The purpose of the present study was to investigate changes in spatial learning and memory in mice after extraction of maxillary and/or mandibular molar teeth, in addition to investigating the neural mechanisms underlying that change.
Male ddY mice, 30 weeks old, were used. In each experimental group, the molar teeth on both sides were extracted as follows: Maxillary, mandibular, both maxillaryand mandibular, and no extraction group as control. Spatial learning and memory were measured by performance in an 8-arm radial maze 1, 7 and 20 weeks followingextraction. Following completion of these behavioral tests on all four groups, histological investigation was carried out by pyramidal cell count of tissue samples (Nissl staining) from the frontal section in CA 1, CA 3 and CA 4 of the hippocampus.
The experimental group showed significantly slower search times and an increase in error rate, compared to the control group. The experimental groupshowed a significant decrease in the number of hippocampal pyramidal cells compared to the control group. A further decline in both spatial memory and the number of cells was observed, especially in the maxillary molar loss group.
In conclusion, it was found that spatial memory and neurological changes of the brain were impaired by the loss of tooth after a long time.
