Development of Labeled Magnitude Scales for Dentine Hypersensitivity

The subjective nature of pain makes its objective measurement and assessment difficult, particularly with persistent episodic pain conditions such as dentine hypersensitivity (DH). Visual analog scales (VAS), typically used in the assessment of DH, are subject to floor and ceiling effects, and between-subject variation can be significant. Labeled magnitude scales (LMS) are a form of VAS that use descriptive terms to demarcate levels of a construct along a continuum. OBJECTIVES: To develop and test 100-mm LMS measures to assess the pain of DH. METHODS: Through focus groups and interviews of individuals (n=26) with clinically diagnosed DH descriptive terms for the pain of dentine hypersensitivity were identified and grouped into four categories: Intensity, Duration, Tolerability and Description. Individuals with DH (n= 24) and healthy controls (n=24) next took part in magnitude estimation tasks to determine the precise location of the descriptors along each scale. Finally, individuals with DH (N=20) completed the resulting scales after dentine stimulation of eligible teeth with 4ºC and 25ºC water. The order of stimuli was randomised. RESULTS: All four LMS measures were sensitive to differences in pain elicited by 4ºC and 25ºC water. Mean differences between pain reports for the two water temperatures were 24.9 mm (t=2.3, p<0.001) for intensity, 10.2 mm (t=2.3, p<0.05) for Duration, 16.4 mm (t=4.1, p<0.001) for Tolerability, and 31.6 mm (t=4.4, p<0.001) for Description. CONCLUSIONS: The LMS measures were sensitive to differences in DH pain sensations between two water temperatures, suggesting these scales may be used to assess changes in DH severity. Further research will involve direct comparisons of the LMS and VAS measures, and will qualitatively examine participants' experiences in using both types of scales. Supported by GlaxoSmithKline.