|
PATIENT
VISIT 3–
Maxillomandibular Records
Clinical
Procedures
Vertical Relations
The physiologic rest
position is the starting point from which the vertical relation of
occlusion is established for the edentulous patient. You should use
as many of the clinical methods available to determine this vertical jaw
relation, for it can be difficult clinical procedure.
The vertical
relation of the occlusion represents the distance the mandible is
separated from the maxilla when the denture teeth are in maximum
contact. The vertical relation of rest position is a physiologic
position established by muscles and gravity. The difference between
the vertical relation of occlusion and the vertical relation of rest is
called the interocclusal distance.
The interocclusal distance is the
space that exists between the denture teeth when the mandible is at the
physiologic rest position. In the edentulous patient. the amount of
interocclusal distance in the existing dentures can be measured and serve
as a guide when determining the amount required for this
patient.
Procedure
click here for video 1. Remove the maxillary record base from the
face-bow and place it in the patient's mouth.
2. Seat the
patient in a comfortable upright position unsupported by a head
rest. Mark a small dot on on the nose and the chin to serve
as reference points. Ask the patient to swallow and relax the jaw
several times.
3.
Use a tongue depressor blade to record the distance between the reference
points when the patient's jaws are in the physiologic rest position.
This measurement is the vertical relation of
rest (VDR) on the tongue blade. It should be relatively constant
after several repetitions.
Only
maxillary record base and occlusion rim inserted to provide lip
support.
4. Mark the tongue depressor
blade 2-3 mm short of the vertical relation of rest. This is the
vertical relation of occlusion (VDO) for most patients.
5. The mandibular
record base and occlusion rim is adjusted by trimming the wax rim with a
heated spatula or knife. If you are having difficulty, check to see
if the acrylic record bases are touching posterior to the to the wax
occlusion rims. Replace the mandibular record base in the mouth and
verify using the tongue blade that you have established the vertical
dimension of occlusion you desire.
Other clinical aids in
determining the vertical dimension of occlusion are facial appearance and
phonetics.
Facial appearance
The rest position of the mandible
affects the harmony of the facial muscles. An experienced clinician
can use this as a further check of the vertical relations. If the
mandible is over closed, the lips and the mandible appear protruded.
If the mandible is held open from the rest position, a strained appearance can be evident when the lips are brought
into contact. Observe your patient in the established rest
position. He or she should appear neither strained nor suffer a loss
of vertical face height. Ask the patient to swallow and see if he or
she appears to strain to bring the teeth into contact while
swallowing.
Phonetics
Speech movements can also be used to
verify the vertical relations. The wax occlusal rims must contact
evenly prior to evaluating the vertical relation of occlusion. The
vertical relation of occlusion should now be verified using
phonetics.
1. Place both maxillary and mandibular record bases
in the patient's mouth. Ask the patient to wet the upper lip with
the tip of the tongue.
2. Ask the patient to say words with "S" sounds,
such as 77 Sunset Strip, 66, count from 1-10, or from 60-70.
3.
Observe from the profile and frontal view that there is 1-2 mm of
clearance between the incisal edges of the occlusion rims in the midline
when the patient repeats the words containing "S" sounds. The space
that exists when these words are said is called the
closest speaking
space. If there is a space of 1-2 mm between the incisal edges of
the maxillary and mandibular occlusal rims in the midline when the patient
says an "S" sound, there should be adequate interocclusal distance.
If the occlusion rims contact when these words are said, then wax on the
mandibular occlusion rim should be removed until this clearance is
obtained.
When you are satisfied that the vertical relation of
occlusal you have established is correct for your patient and your
occlusion rims occlude evenly anteriorly and posteriorly, you are ready to
record centric relation.
Centric relation
click here for video 1. Practice guiding your
patient into centric relation with the record bases in the patient's
mouth. Instruct the patient place the tip of the tongue in the
palate. You must hold the mandibular record base in position with
your hands when making a centric relation record for complete denture
patients as the mandibular record base can lift away from the patient's
tissues invalidating your records.
2. Place the occlusion rims
in the patient's mouth and verify that both rims occlude evenly on
closing. Adjust the rims if they do not. Close the patient
into centric relation. Scribe a line on the right and left sides of
the mandibular rim below the canine lines of the maxillary occlusion
rim. This line will serve as a guide anteriorly when removing wax
form the posterior side of the mandibular occlusion rim.
3. Remove a
strip of the posterior occlusion rim approximately 1 mm in depth from the
mandibular occlusion rim on both sides posterior to the marks just
made. After removing the wax, cross hatch the surface of the
remaining wax with the tip of a sharp knife to serve as mechanical
retention for the recording medium.
4. Make two nonparallel V-shaped
grooves on the right side of the maxillary occlusion rim, one in the
premolar area and one in the molar area. They are located above the
cross hatched surfaces of the mandibular occlusion rim. These
grooves should not be more than 2 mm in depth. Repeat on the left
side of the maxillary occlusion rim.
click here for video
5. Lubricate the grooves and the
buccal, lingual and the occlusal surfaces of the maxillary wax rim with
Vaseline.
6. Place the maxillary record base in the patient's mouth and
check it for retention and stability. If it is unstable or
non-retentive, small amount of denture adhesive may be necessary.
7. Bite Registration Paste or Aluwax can be used as a recording medium.
8. Place a small amount of
material on the mandibular occlusion rim in the area of the premolars and
molars. Carefully place the record base in the patient's mouth and
slowly guide the patient into centric relation. Hold the mandibular
record place in position with your index fingers when guiding the patient
into centric relation. wait for the material to set according to the
manufacturer recommendations. Always hold the record in place yourself.
Note: The centric relation record is valid only at the established
vertical relation of occlusion. Your record of the vertical relation
of occlusion is preserved in the anterior portions of the wax rims.
Take care to note that wax rims are contacting anteriorly when you make
your centric relation record.
9. After the recording medium has
set, remove the record base from the patient's mouth and inspect it.
There should be no contact between the acrylic bases, wax rims, or master
casts. Trim excess recording material carefully with a warm sharp
knife blade.
10. Return the record to mouth and check it for
repeatability. This record must be repeatable.
|