Several rechargeable electric toothbrush models offer pressure sensors to monitor the force being applied by the user when brushing. Pressure sensors alter the brush movement to make patients aware when too much pressure is being applied. Many electric toothbrushes are equipped with a light which illuminates when too much pressure is applied (Figure 7a). The new Oral-B iO power toothbrush is the first to have a smart pressure sensor that also indicates when the user is not applying enough pressure and when the user is in the optimal pressure range for plaque removal and safety (Figure 7b). And, if too much pressure is being applied, the electronically controlled linear magnetic drive automatically reduces the oscillation angle to operate in the ‘sensitive’ mode.9
Brush filaments are made of soft end-rounded nylon in various diameters. Endrounding occurs during the manufacturing process after the bristles are inserted into the brush head. The bristles are sanded and then polished to a smooth rounded tip. A bristle’s stiffness is directly related to its diameter and length: thicker bristles require more force to bend than thinner bristles. Soft bristles are preferred because hard bristles may abrade the gingiva. Now, most manufacturers use endrounding technology to ensure safety for both hard and soft tissues in the oral cavity.