Vertical jaw movement and normalized masseter EMG activity (NU) for the dentate (solid curves) and implant participants (dashed curves) during single cycles of chewing on hard food. Data shown for the beginning (A), middle (B) and end (C) of the masticatory sequence are the averages for all participants and chewing cycles in each group (following normalization of each phase to the mean duration of that same phase for all participants in each group). Grey areas indicate SE (N = 13) and the data have been aligned temporally to the start of the occlusal phase (time = 0). The vertical lines to the left and right indicate the start of the closing phase (peak jaw-opening) and end of the occlusal phase, respectively. Op, Cl and Oc indicate the jaw-opening, jaw-closing and occlusal phases, respectively. The inset illustrates the rate of change in the average EMG signal.