Figure 1. Transducers for lip-pressure measurements in the incisal and cervical areas of both maxillary central incisor crowns. (A) Four pressure sensors were attached to a carrier halfway in the mesio-distal dimension of the crowns so that the lowest edges of the 2 incisal sensors were level with the incisal edges of the maxillary centrals. (B) Dimensions and attachment levels of sensors and pressure-receiving surfaces.