The design of the new Ortho brush head differs from the regular Emmi-dent brush head, the middle row of the bristles is shorter so they touch the wire from the braces to clean them. Other bristles have been rearranged so they are positioned close to the brackets to optimise the cleaning power of ultrasound even underneath. Ultrasound is generated by an ultrasonic capable microchip directly inside the Emmi-dent brush head. The chip creates the ultrasonic impulses and transmits them via each bristle and the nano-bubble toothpaste directly onto the surface and the gum. Billions of nano-bubbles cover the teeth and gums, imploding through the ultrasonic impulse and destroying plaque, tartar, food scraps, bacteria, etc. Emmi-dent is a no-brush toothbrush. Patients clean their teeth by holding the brush over three teeth or equivalent area of gums for five to ten seconds, then moving the brush and holding it again for five seconds over the next three teeth or gum area. Emmi-dent brush head features: Contains a specially patented ultrasonic microchip Cleans with-out friction or motion Promotes healthier gums, reverses gingivitis and gum bleeding It is recommended that you replace your Emmi-dent ultrasonic toothbrush head every three months. A worn Emmi-dent brush head transmits less ultrasound through its bristles and therefore does a less effective job of cleaning your teeth