The adaptive system includes a power toothbrush (10) which determines bristle force or pressure applied by the user against the teeth. The toothbrush includes a processing system (28) for comparing the determined force with a threshold value of excessive force and a threshold adaptive value which is below the excessive force threshold but serves as a warning for the user. The system is capable of raising the initial adaptive value threshold (64) following the user exceeding the adaptive value for a selected number of brushing events and then further for decreasing the adaptive value (66) back toward the initial adaptive value when the increased adaptive value is not exceeded for a selected number of brushing events, thus providing the ability to encourage/coach the user toward a brushing force which is below the threshold adaptive level and into a safe region of operation.