Aims: To evaluate a method for self-registration of maximum
mandibular opening capacity by means of a spatula and estimation
of vertical overbite from photos. Methods: The study group
consisted of 50 adults. Each participant received written instructions,
photos, a measuring spatula, and a pencil. The first task was
to register maximum interincisal distance. The participant opened
up his or her mouth as wide as possible, looked in a mirror, and
marked the distance on the spatula. The second task was to estimate
the vertical overbite in the intercuspal position. A clinician
then estimated the type of overbite and measured the maximum
interincisal distance and the vertical overbite with a ruler in millimeters.
Results: The normal overbites showed a mean value of
2.4 mm, and a standard value of 2 mm was set. The deep bites
showed a mean value of 5.2 mm, and a standard value of 5 mm
was set. The standard overbite value, added to the value measured
on the spatula, was compared with the clinical values made by the
clinician for maximum mandibular opening. The limits of agreement
for 95% of the mean difference were –4.2 mm and 4.4 mm.
Six people missed the correct diagnosis for the vertical overbite.
Conclusion: The self-registration method of measuring maximum
mandibular opening capacity seems valid for studying major differences
in opening capacity when clinical measurements are not
possible to perform. J OROFAC PAIN 2003;17:341–346.