Hostility in TMD/bruxism patients and controls: a clinical comparison study and preliminary results.

This study involved a group of 110 TMD/bruxing behavior patients (30 mild, 40 moderate, and 40 severe bruxers) which was compared to a group of 40 nonTMD/nonbruxer controls, with the objective to test the alternative hypothesis that, regarding hostility, there were significant differences between these groups. The mean age in the group of TMD/bruxers was 31.81 years (SD: 11.2, range 14-61) and in the control group was 30.03 (SD: 10.96, range 16-66). Patients were initially classified as presenting TMD and bruxing behavior according to previous criteria. The Cook-Medley Inventory and the Beck Depression Inventory were used to assess levels of hostility and depression, respectively, in bruxers and controls. There were no statistically significant differences in the levels of depression between the three groups of bruxers. However, the difference between the groups of bruxers and controls reached significance (unpaired t test P<0.001). Our results indicated that there was not statistically and significant difference in the levels of hostility between the three groups of bruxers and between the mild group of bruxers and control group. However, there were statistically and significant differences in the level of hostility between the moderate group of bruxers and the control group (P<0.01), and between the severe group of bruxers and the control group (P<0.05). When bruxers were classified into two groups: one presenting minimal to mild depression (N:31) and the other presenting moderate to severe depression (N:19), the group presenting moderate to severe depression demonstrated a level of hostility of about 23.36. The group presenting minimal to mild depression demonstrated a level of hostility of about 17.32, and this difference was statistically significant (unpaired t test, P<0.0004). These results suggest that in these subgroups of TMD/bruxers, increased depression corresponds to increased hostility and provides support for previous investigations indicating that there is a relationship between hostility and bruxism (but only in the groups with moderate and severe bruxism).