2.3. Orofacial pain

The presence of orofacial pain during rest, drinking, chewing and oral hygiene care was observed in all participants using the Orofacial Pain Scale for Nonverbal Individuals (OPS‐NVI), by a dentist (SD) and trained research assistants.17, 19, 20 With the OPS‐NVI, facial activities, body movements, vocalisations and specific oral behaviours were observed and the presence of pain was estimated and scored on a Numeric Rating Scale from 0 to 10, at which 0 is no pain and 10 the worst pain imaginable.20 A value of 1 or higher was considered as observed pain presence.

Verbal participants were asked about the presence of pain during rest, drinking, eating and oral hygiene care. Furthermore, sensory testing took place, including tests with a cotton roll, brush and probe at the three innervation areas of the trigeminal nerve.21 For the sensory testing, first, a cotton roll was used to make three strokes of one to two centimetres on the left and right skin above the eyebrow (N.opthalmicus), below the eye (N.maxillaris) and below the lower lip (N.mandibularis). Thereafter, the test was repeated with a brush and a light pin prick with a dental probe.21 Directly after each test, the participant was asked if pain was present. In addition, pain during active and guided mouth opening was examined. For the active mouth opening, the participants were asked to open their mouths as far as possible. During the guided mouth opening, the participants were asked to relax their jaw as much as possible, while the dentist guided the mouth opening.22 If pain was reported, the guided mouth opening was stopped and the participants were asked whether the pain was familiar to them.23 People with an MMSE score of 14 or higher were considered to present a reliable pain self‐report.24