Black & white drawing
Left - the bristles are forced flat against the tooth by use of excessive pressure, or through a softening of the bristles. In either case, the gingival tissue is apt to be traumatized, and the cervical embrasure omitted during the cleansing process. Center - The bristle ends reaching to, or beyond, the incisal edge of the teeth as a result of excessive pressure with the brush. Whenever the incisal edges are so obscured from sight in the Charters type stroke, it may safely be taken for granted that despite the hard brushing, the necks of the teeth remain uncleansed, and the gums, untouched. Right - excessive angle of the brush to the tooth, which patients instructed in the Charters type stroke erroneously understand to be correct, believing that the teeth are to be brushed with the sides of the bristles, and the gum massaged by the hard part of the brush-head.
This work is dedicated to the Public Domain.