Purpose: To evaluate and compare the changes in brain activity for individuals with a single missing mandibular molar replaced with a removable dental prosthesis (RPD) and a fixed tooth-supported implant prosthesis in the static and postmasticatory phases. Materials and Methods: In total, 24 patients with a unilateral missing mandibular first molar were rehabilitated with a removable dental prosthesis and divided into two groups of 12 each; Group A was rehabilitated with implants and Group B with 3-unit tooth-supported fixed partial dentures (FPDs). An electroencephalogram (EEG) was taken during the three phases of assessment: (1) before insertion of any prosthesis (N0), (2) after insertion of an RPD (N1), and (3) after cementation of an FPD or implant crown (F2). The effect of bite force with RPD (N1M) and FPD or implant prosthesis (F2M) on alpha waves was evaluated by recording EEG immediately after chewing gum for 30 seconds. Results: The improvement of the amplitude of alpha waves before and after prosthesis insertion showed a significant difference between Group As and B (P < .05) with the highest mean values of 158.3 µV, 147.9 µV, and 182.1 µV occurring in pairs F2-N0, F2-N1, and F2M-N1M, respectively, for Group A. Similarly, for the power of alpha waves between group A and B, a statistically significant difference (P < .05) with the highest mean values of 30.3 dB, 28.9 dB, 36.9 dB, and 11.2 dB in pairs F2-N0, F2-N1, F2M-N1M, and F2M-F2 ,respectively, was observed for Group A. There was no statistically significant increase in pair N0-N1 (P > .05). Conclusions: Replacement of a single missing tooth enhanced brain activity and was highest with an implant-supported crown. Int J Prosthodont 2023;36:563–569.