Test–retest reliability of quantitative sensory testing for mechanical somatosensory and pain modulation assessment of masticatory structures

Abstract

Assessing the reliability of medical measurements is a crucial step towards the elaboration of an applicable clinical instrument. There are few studies that evaluate the reliability of somatosensory assessment and pain modulation of masticatory structures. This study estimated the test-retest reliability, that is over time, of the mechanical somatosensory assessment of anterior temporalis, masseter and temporomandibular joint (TMJ) and the conditioned pain modulation (CPM) using the anterior temporalis as the test site. Twenty healthy women were evaluated in two sessions (1 week apart) by the same examiner. Mechanical detection threshold (MDT), mechanical pain threshold (MPT), wind-up ratio (WUR) and pressure pain threshold (PPT) were assessed on the skin overlying the anterior temporalis, masseter and TMJ of the dominant side. CPM was tested by comparing PPT before and during the hand immersion in a hot water bath. anova and intra-class correlation coefficients (ICCs) were applied to the data (α = 5%). The overall ICCs showed acceptable values for the test-retest reliability of mechanical somatosensory assessment of masticatory structures. The ICC values of 75% of all quantitative sensory measurements were considered fair to excellent (fair = 8·4%, good = 33·3% and excellent = 33·3%). However, the CPM paradigm presented poor reliability (ICC = 0·25). The mechanical somatosensory assessment of the masticatory structures, but not the proposed CPM protocol, can be considered sufficiently reliable over time to evaluate the trigeminal sensory function.

The effect of orthodontic separator and short‐term fixed orthodontic appliance on inflammatory mediators and somatosensory function

“…Finally, we also found significant baseline differences on the tactile sensitivity, that is, MDT, which could indicate differential somatosensory sensitivity within the trigeminal territory. Indeed, previous investigations have reported somatosensory differences within the trigeminal innervation when considering anatomical areas related to masticatory muscles and the temporomandibular joint (TMJ) . Further researches are encouraged to establish a systematic somatosensory mapping of the trigeminal region.…”

“…MDT was performed as previously described using a standardised set of Semmes‐Weinstein monofilaments*, which apply forces between 0.008 g/mm 2 and 300 g/mm 2 . Participants were instructed to report the first perception of touch.…”

“…The “method of limits” technique was used to determine the threshold, where a series of ascending and descending stimuli intensities were applied yielding five suprathreshold and five subthreshold reports. The MDT was the geometric mean of these five series …”

“…The procedure was repeated five times. The WUR was the mean rating of the five series stimulus divided by the mean rating of the five single stimuli …”

“…Inflammation can also alter nerve function, and it has been shown that the release of IL‐1β and TNF‐α induce inflammatory hyperalgesia, characterised by a decrease in the nociception threshold and increase neuronal membrane excitability, which can lead to somatosensory alterations . Quantitative sensory testing (QST) is a standardised battery of psychophysical tests that can reliably assess the somatosensory function and has been extensively applied to the oro‐facial region . Although recent studies have reported intraoral somatosensory alterations following orthodontic appliance, there is no evidence if these possible alterations can also be detected at extraoral trigeminal locations.…”