Effect of experimental occlusal interferences on temporomandibular pain and tooth contact

Background Temporomandibular disorders (TMDs) are highly prevalent in the general population but their etiology and pathophysiology are scarcely known. This study tested the hypothesis that experimental occlusal interference (i.e., a disturbance to the habitual bite closure) induces an increase of non-functional tooth contacts as well as TMD-like pain symptoms, in subjects who report frequent parafunctional (i.e., non-functional) oral behaviors. Method Two parallel groups were selected by means of a questionnaire for oral behaviors. The first group (P) included subjects (n=10; mean age ± SD = 22.3 ± 1.8 yrs) reporting severe parafunctional habits whereas the second group (NP) included subjects (n=10; mean age ± SD = 20.4 ± 1.2 yrs) who reported the occurrence of parafunctional habits only sporadically. In order to establish how often each subject kept the teeth in contact during the waking hours, a microprocessor-controlled recorder was used. Perceived pain and headache were assessed by visual analogue scales (VAS). Assessments were taken over nine consecutive days, through three sessions of three days each (i.e., before (T0), during (T1), and after (T2) the application of the occlusal interference). The statistical analysis was performed using non parametric methods. Results and conclusions At T0, there were no significant differences between the two groups for all the variables considered. The frequency of non-functional tooth contacts decreased significantly at T1 only in group NP (p=0.01). Perceived pain and headache VAS scores increased significantly only in group P (p=0.05 and 0.04, respectively). Subjects reporting severe parafunctional habits reacted differently to the introduction of an experimental occlusal interference.