Effect of Height of Occlusal Interference on Dopamine Release in the Prefrontal Cortex of Rats

Abstract

Purpose : To clarify the relationship between the height of occlusal interference and stress responses by measuring the amount of dopamine released in the prefrontal cortex of rats.Materials and Methods : Aluminum laminate (0.5, 1.0 or 2.0 mm thick) was fixed to the maxillary left molar to interfere with the occlusion of the rats. No laminates were fixed in the control rats. The amount of dopamine released in the prefrontal cortex was measured by microdialysis before and after fixing the laminate. After fixing the laminate, the dopamine was measured for 360 minutes in experiment 1. In experiment 2, it was measured for 180 minutes and later measured for an additional 180 minutes after the rats were given 20 minutes to eat a food pellet.Results : In experiment 1, the amount of dopamine released in the prefrontal cortex was not significantly different among the groups during the 360 minutes following the operation to insert the laminate. The amount of dopamine released in experiment 2 increased only in the rats with an occlusal interference of 0.5 mm (p=0.04). Furthermore, a comparison of the amount of dopamine released before and after feeding within each group indicated that the only significant change was an increase during the 60 to 100-minute period after the 20-minute feeding session in the 0.5 mm group.Conclusion : The amount of dopamine released in the prefrontal cortex of rats in this study was influenced by the height of occlusal interference. Low (0.5 mm) occlusal interference was more stressful than higher (1.0 and 2.0 mm) occlusal interference.