OR27 - Validation of a Simplified and Cost-effective Approach to Measure Orofacial Mechanical Pain Thresholds in Humans

Abstract: Central sensitization in odontogenic pain patients results in mechanical allodynia in sites distant from the symptomatic tooth. Quantitative sensory tests currently used to detect mechanical allodynia include the use of Von Frey filaments. However, their use in Endodontic practice is limited by their cost. To address this problem, we developed cost-effective, single-use Von Frey filaments. The objectives of this study are (1) to confirm the forces exerted by the filaments and, (2) to test their reliability in measuring the intra- and extra- oral pain thresholds. A high precision laboratory scale was used to measure forces exerted by the different Von Frey filaments. Five sets of filaments were tested three times each by two independent observers. To test their reliability in measuring pain thresholds pain free volunteers were recruited (N=16). Pain thresholds were measured on the attached gingiva over first molars bilaterally in both arches and extraorally. Inter- and intra- examiner reliability, and site/gender differences were analyzed using the intraclass coefficient or paired t-test, respectively, with significance set at (p < 0.05). Results of our in vitro study show that the single use Von Frey filaments consistently measure applied forces in an accurate manner (r2= 0.937) over a range of 80-350mN. Conclusions: A single use cost-effective mechanical allodynia testing device was developed and allowed for measurements of pain thresholds with high reliability and reproducibility. This method can be broadly used in everyday endodontic practices to quantify mechanical allodynia to inform clinicians of possible necessary treatment modifications.