Methods: Sixteen healthy volunteers participated. Three different palpometers with different force levels (0.5, 1.0 and 2.0 kg) were used. Add-on devices were put on the circular metal stamp of the palpometer. Four different diameters (3, 4, 5 and 10 mm) and two different shapes of the rubber-top (flat and round) were applied, i.e. a total of 24 different combinations (3 force levels x 4 diameters x 2 shapes). Participants were stimulated at the gingival mucosa around the upper incisal and molar teeth on the right and left side using 24 types of the palpometer in randomized order. After each stimulation, participants were asked to rate the perceived intensity of the stimulus on a 0-50-100 numerical rating scale (NRS). Ten of the volunteers were examined twice on the same day and recalled for a second session for assessment of within- and between-session reliability of selected stimulus types.
Results: Reliability of the NRS scores was excellent (interclass correlation coefficients 0.76 - 0.99). The analysis of the NRS values corrected for pressure level revealed that there were main effects of site (P < 0.010), force (P < 0.001), size (P < 0.001), and shape (P < 0.001) but not side (P > 0.050).
Conclusions: In conclusion, the reliability of intraoral novel palpometer measures of pressure sensitivity was excellent and the sensitivity to the pressure stimulus was dependent on the applied force and physical properties of the add-on device.