Development and validation of the Manchester oro-facial pain disability scale.

Objective: To design and validate a self-administered instrument for assessing orofacial pain related disability in the general population. Methods: The 32-item questionnaire was developed by open-ended interviews with patients attending dental hospital clinics and was subsequently tested on 171 community subjects with self-reported orofacial pain and 48 dental hospital patients. Results: Construct validity of the instrument was demonstrated in three ways. First, levels of reported disability were greater in dental hospital patients than for community subjects reporting orofacial pain. Secondly, the instrument was able to detect differences in disability levels reported by community subjects who did and did not consult with a healthcare professional and those who had acute and chronic pain. Thirdly, amongst community subjects with pain, disability scores increased with higher pain intensity, pain duration and were greater amongst subjects who had sought a consultation. Results of factor analysis identified two constructs: physical and psychosocial disabilities, associated with orofacial pain. The Cronbach's alpha score was 0.78 and 0.92 for the physical and psychosocial constructs, respectively, and this along with item correlation values between 0.43 and 0.80 confirmed the internal consistency. Conclusion: We have therefore designed a valid instrument for assessing the impact of painful orofacial conditions in both community and clinic settings.