The American Dental Association (ADA) recommends replacing your brush head every 90 days, after you've been sick, or when the bristles begin to fray or fade. Prevent bacteria build-up and make it part of your healthy oral care routine... swap your brush head on schedule. We carry all replacement brush heads for all the Triple Bristle sonic toothbrush models and handles - the Original sonic, the Kids sonic, the Travel Go, the Max, the Duo model, and the special needs handle. Additional replacement heads compatible with most Philips Sonicare® toothbrush models are also available. TRIPLE-sided sonic brushing for all!