2010 RWISO Journal - Roth Williams International Society of ...

sure was first checked in the mounting on the true hinge ar-
ticulator and then checked intraorally with and without the
positioner. The patient was instructed to wear the positioner
full time for the first 3 days (with the exception of eating and
brushing). After the first 3 days, the patient was instructed to
wear the positioner at night, with 4 hours of positioner exercise
during the day. If the positioner should fall out during
the night, the patient was instructed to wear the positioner
for 6 hours during the day.
Positioner Exercise and Wear Protocol
The patient was instructed to bite into the positioner just
enough to seat all of the teeth and to fully engage the teeth in
the positioner. The patient was instructed to bite with pressure
for about 10 seconds and then to relax for about 15
seconds. The exercise was done in 15-minute intervals, with
15 to 20 minutes of rest in between. For nighttime wear, the
patient was instructed to put the positioner into the mouth
and close the mouth to engage the positioner as much as possible
without putting pressure on the positioner.
The gnathologic positioner was checked for fit and arc
of closure at 1, 2, and 4 weeks after delivery. After 2 months
of positioner wear, postpositioner records were taken (time
2). These consisted of the same records that had been taken
at time 1. Upper splint and lower spring retainers were then
delivered.
The control group consisted of 8 randomly selected
finished cases in the orthodontic clinic at the University of
Detroit Mercy. The control group was not preselected with
regard to MI-CR discrepancy at debond. At the debonding
appointment (time 1), braces were removed and records
were taken. Upper and lower Hawley retainers were delivered,
and the patient was instructed to wear them full time.
After 2 months of Hawley retainer wear, records were taken
again (time 2).
MI-CR discrepancy was measured with a CPI (Panadent
Corporation, Grand Terrace, California) at times 1 and 2 for
both groups (Figure 4,5).
Results
The mean differences between MI and CR of the articulators’
condylar axis position were recorded for the transverse,
and separately for the right and for the left condyles in the
vertical and anteroposterior (A-P) directions. Pre- and posttreatment
measurements of MI-CR discrepancy of the control
and positioner groups are summarized in Table 1.
Figure 4 CPI registration with two-piece CR bite (A).
CPI registration with MI bite (B). CPI Recording – transverse (C).
CPI Recording – right (D).
Figure 5 Condylar position indicator recording graph
(CR – red dot, MI – blue dot).
RWISO Journal | September 2010
77