Clinicians should recognize that the frequency and intensity of daytime clenching are noticeably increased in individuals with masticatory muscle pain in order to better tailor treatment.

Objectives To assess the association between waking‐state oral behaviours and temporomandibular disorder (TMD) subgroups and to develop new scoring methods for the Oral Behavior Checklist (OBC). Methods Patients with any TMD diagnosis, according to the diagnostic criteria for TMD (DC/TMD), were divided into subgroups: ‘Dysfunctional‐TMD’ (n = 70), only mechanical dysfunction; ‘Painful‐TMD’ (n = 204), only myalgia, arthralgia or both; and ‘Painful‐Dysfunctional TMD’ (n = 95), combined pain and dysfunction. A group of individuals without TMD, ‘Non‐TMD’ (n = 374), was used for testing associations. Participants completed the OBC. An exploratory factor analysis, followed by a confirmatory factor analysis of the OBC responses, identified 2 major factors, named non‐functional activities (NFA) and functional activities (FA). Component total scores were computed. Differences among subgroups for OBC‐MS (mean score) and NFA and FA factor scores were estimated using one‐way ANOVA and Tukey post hoc tests. Significance was set at p < .05. Results The OBC‐MS in Non‐TMD, Painful‐TMD and Painful‐Dysfunctional TMD subgroups was higher than in the Dysfunctional‐TMD subgroup (p ≤ .001). NFA in Painful‐TMD and Painful‐Dysfunctional TMD subgroups were higher than in the Non‐TMD group (p < .05); NFA in the Dysfunctional‐TMD subgroup were lower than in the Painful‐TMD subgroup (p = .034). In contrast, FA in Painful‐TMD, Dysfunctional‐TMD and Painful‐Dysfunctional TMD subgroups were lower than in the Non‐TMD group (p < .0001). Conclusions A new scoring method for the OBC results in item reduction and creation of meaningful subscales for functional and non‐functional behaviours, which are differentially associated with painful and dysfunctional TMDs. This may help clinicians to better tailor treatment for the management of subtypes of TMD patients.

Summary Background The Oral Behaviours Checklist (OBC) is a valid 21‐item instrument quantifying the self‐reported frequency of oral behaviours. An Italian version (OBC‐It) has been released recently. Anxiety and oral behaviours are known to be associated in individuals with oro‐facial pain due to temporomandibular disorders (TMD). However, information about this relationship in pain‐free individuals is still limited. Objectives The aim of this study was to test the reliability of the OBC‐It and its reduced version (OBC‐It 6), focusing on tooth clenching‐related wake‐time oral behaviours, and the effect of patient instructions on reliability. A second aim was to test the association between trait anxiety and oral behaviours in pain‐free individuals. Methods Two hundred and eighty‐two TMD‐free students, divided into 2 groups (Group A, n = 139, mean age ± SD = 22.6 ± 5.4 years; Group B, n = 143, 23.7 ± 4.2 years), filled in the State‐Trait Anxiety Inventory and the OBC‐It. Group B received instructions about the OBC‐It, while Group A did not. After 2 weeks, both groups filled in the OBC‐It again. However, Group B was further divided into 2 subgroups, B1 and B2. The first received the same instructions again, while B2 did not. Results The test‐retest reliability of the OBC‐It (A: ICC = .87; B1: ICC = .94; B2: ICC = .95) and OBC‐It 6 (A: ICC = .85; B1: ICC = .89; B2: ICC = .93) was excellent in all groups. Trait anxiety was weakly associated with OBC‐It only in women (R2 = .043, P = .021). Conclusions The OBC‐It is a reliable tool but further subjects’ instructions might be needed. Trait anxiety has a limited effect on oral behaviours in TMD‐free subjects.