Occlusal features are not a reliable predictor for bruxism

The aim of this investigation was to estimate the contribution of occlusion
to differentiate bruxers from non-bruxers. METHODS: Participants in the study
were 160 patients consecutively selected among 20-30 year old patients attending
the Section of Prosthetic Dentistry for conservative care. The presence of
bruxism was clinically and anamnestically investigated. In each patient the
following occlusal features were recorded: retruded contact position-intercuspal
position slide length, vertical overlap, horizontal overlap, unilateral posterior
crossbite, incisor dental midline discrepancy, mediotrusive interferences,
laterotrusive interferences. A stepwise logistic regression model was used to
identify the significant associations between occlusal features and bruxism.
RESULTS: Diagnosis of bruxism was made in 67/160 subjects (41.8%). Differences
between sex were not significant (p=0.814). Among the 8 occlusal variables
included in the logistic regression analysis, those remaining in the final model
were laterotrusive interferences (OR 2.47) and anterior open-bite (OR 0.88). This
model showed good specificity (87%) but an unacceptable sensitivity (26.9%) to
predict bruxism (accuracy=61.6%). Therefore, multivariate analysis did not lead
to an improvement in bruxism predictability with respect to univariate analysis,
which revealed that the presence of bruxism was significantly associated with
laterotrusive interferences alone (p=0.040), and not with unilateral cross-bite
(p=0.208), anterior open-bite (p=0.202), deep-bite (p=0.572), large horizontal
overlap (p=0.261), dental midline discrepancy (p=0.519), mediotrusive
interferences (p=0.119), slide >or=2 mm (p=0.857). CONCLUSION: According to our
findings the contribution of occlusion to differentiate bruxers from non-bruxers
is very poor. Infact, only laterotrusive interferences seem to be significantly
associated with bruxism.