Purpose: Implant therapy restores masticatory function by restoring lost tooth
morphology. It has been shown that mastication contributes not only to food
intake and digestion, but also to the improvement of overall health. However,
there have been no studies on the effects of implant treatment on electroencephalography
(EEG). In this study, we investigated the effects of restoration of masticatory
function by implant treatment on EEG and stress. Methods: 13 subjects (6 males, 7 females, age 64.1 ± 5.8
years) who had lost masticatory function due
to tooth loss and 11 healthy subjects (6 males, 5 females, age 47.6 ±
2.4 years) as a control group. EEG (θ, α, β waves, α/β ratio) and salivary cortisol were
measured before immediate dental implant treatment and every month of treatment
for 6 months. EEG (θ, α, β waves, α/β ratio) was measured with a simple electroencephalograph miniature
DAQ terminal (Intercross-410, Intercross Co.,
Ltd., Japan) in a resting closed-eye condition, and salivary cortisol was measured using an ELISA kit. Results: Compared to the control group, the appearance of θ and α waves were significantly decreased and β waves were increased, and α/β ratio was significantly decreased. The cortisol level of the subject
group was significantly higher compared with the control group. With the course
of implant treatment, the appearance of θ and α waves of the subject group
increased, while β waves decreased.
However, no significant difference was
observed. The α/β ratio of the subject group increased from the first month
after implant treatment and increased significantly after 5 and 6 months (0 vs.
5 months: p < 0.05, 0 vs. 6 months: p < 0.01). The cortisol levels in the
subject group decreased from the first month after implant treatment and
significantly decreased after 3 or 4 months (0 vs. 3 months: p < 0.05, 0 vs. 4 months: p < 0.01). These results
suggest that tooth loss causes mental stress, which decreases brain
stimulation and affects function. Restoration of masticatory function by
implants was suggested to alleviate the effects on brain function and stress.
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