Aims: To test the hypothesis that estimates of time spent in tooth contact are significantly greater than estimates of time spent clenching, and to test the hypothesis that tooth contact is greater in pain patients, particularly those reporting facial or head pain, than those with pain elsewhere in the body. Methods: An anonymous, voluntary, confidential questionnaire was administered to 235 patients seeking care at a general medical clinic. The questionnaire assessed demographic variables, presence and location of pain, and percentage of time spent in tooth contact and in clenching. Analysis of variance was used to examine differences among groups of patients; logistic regression was used to identify significant predictors of pain. Results: All patients reported that the percentage of time spent in tooth contact was significantly greater than the time spent clenching. The same pattern of results emerged for those with and without head pain, and those with and without any chronic pain problem. Both tooth contact and clenching were significantly associated with head pain. Conclusion: Results from the logistic regressions provide convergent validity on the importance of oral parafunctions, specifically tooth contact and clenching, to facial/head pain. For assessment of oral parafunctional behaviors, inquiries that utilize clear behavioral referents (tooth contact versus clenching) are likely to result in more accurate estimates than behaviors with unclear definitions. Palabras clave: clenching, oral parafunction, pain, tooth contact