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

Materials and Methods
The records of 51 patients—34 females and 17 males—treated
in a gnathologically oriented practice constituted the sample.
Subjects ranged in age from 13 to 57 years, and all had
unremarkable medical histories with no contraindications to
orthodontic treatment. All upper and lower permanent teeth,
except third molars, were present on all subjects. TMJ exams
were conducted by a single operator before orthodontic records
were conducted. Evaluation included subjective symptomatology,
as well as clinical examination. Subjects who
presented with TMJ symptoms were placed on a gnathological
maxillary splint for a minimum of 3 months, or until
subjects were symptom free. Twenty of the 51 subjects had
records taken after splint therapy. The remaining 31 subjects,
all in active orthodontic treatment and with asymptomatic
TMJ, had records taken one appointment prior to deband.
All subjects had two maxillary alginate impressions taken
using Jeltrate alginate (Dentsply, Milford, Delaware). The
impressions were taken using sterilized metal rim lock trays
(Dentsply, Milford, Delaware). All impressions were disinfected
using Sterall Plus Spray (Colgate-Palmolive Company,
Canton, Massachusetts), and were rinsed with water and air
dried before being poured up.
All impressions were wrapped in moistened paper towels
and placed in plastic bags for approximately 20 minutes
prior to being poured up with Velmix (KerrLab, Orange,
California). Each model was poured up utilizing a waterpowder
ratio consistent with the manufacturer’s instructions
for Velmix. The Velmix was vacuum mixed to remove any
entrapped air. The models were trimmed, and all bubbles
were removed from the occlusal surfaces.
Arbitrary earpiece face-bow transfers using the external
auditory meati were taken on each subject. (Panadent, Grand
Terrace, California) (Figure 1).
48 Freeland et al | Comparison of Maxillary Cast Positions
Figure 1-a, b Estimated facebow.
Figure 1-b
A true hinge face-bow was then taken on each subject,
using the true hinge axis instrument (Panadent, Grand Ter-
race, California) (Figure 2). A single operator completed
both face-bow records within 20 minutes of each procedure.
Intraoperator reliability tests for each of the two transfer
techniques were calculated.