Flat or double-articulating headrest--is there an ergonomic consideration for either?  The answer is a resounding YES, especially when treating the upper arch.  Double-articulating headrests can be angled up into the occiput to gain optimal view of the upper arch (above).  This is an important concept when treating patients who may not tolerate full supine--the double-articulating headrest can be angled backward to compensate for the lack of recline, to get the arch in a better position.  Flat headrests make it more difficult to get the occlusal plane of the upper arch angled optimally backward.  Most flat headrests come with a horseshoe or magnetic headrest, which generally do not support the cervical spine adequately.  The best positioning for the upper arch, using a flat headrest, can be attained using a cervical support cushion (right), with the large end under the neck. But, even then, with flat headrests, the occlusal plane cannot approach the desired 25 degree backward angle for optimal viewing and posture.  These contoured cushions work well for hygiene treatment and can allow for ergonomic positioning throughout the treatment without re-adjusting the patient chair.  The cushion can simply be reversed (large end behind the patient's head) when treating the lower arch.