The aim of this investigation was to compare the pattern of temporomandibular disorder (TMD) diagnoses in clenching patients with different occlusal features, the null hypothesis being that no between-group differences exist.
Two groups of subjects receiving a jaw clenching diagnosis and having large overjet or anterior open bite (Group A; N=45, 75.5% females, mean age: 38.1 +/- 15.9 years) or normal occlusion (Group B; N=69, 71% females, mean age: 34.6 +/- 13.8 years) were recruited among a TMD patient population and were given Research Diagnostic Criteria for TMD (RDC/TMD) axis I diagnoses, namely, group I muscle disorders, group II disc displacements, and group III arthralgia/osteoarthritis/osteoarthrosis.
The distribution of RDC/TMD single and combined group diagnoses was significantly different between the two groups (P<0.05), with Group A subjects showing a higher prevalence of multiple diagnoses (60% versus 43.3%), as well as a higher prevalence of combined RDC/TMD axis I group II and III diagnoses (37.8% versus 20.2%). All TMD signs and symptoms were more frequent in the patients with large overjet or anterior open bite with respect to the patients with normal occlusion.
In a TMD patient population, jaw clenching may have different consequences in subjects with large overjet or anterior open bite with respect to subjects featuring normal occlusion.