Few topics in dentistry evoke emotion or create confusion like
occlusal-related topics. Concepts for making bite records for crown
and bridge reconstruction are no different and can be oversimplified
or overcomplicated depending on the clinical scenario.
Treatment involving a single crown requires less sophistication in
bite recording and is generally made using a conformative or existing
intercuspal recording (MIP). Recording a bite for preparations
in a free end quadrant can be more complicated because there are
no occlusal stops in the quadrant being restored. However, there
are generally enough existing intercuspating teeth to enable a bite
record that does not require assignment of a new vertical dimension
or a condylar position. When a full arch has been prepared
and there are no longer any occlusal anatomical landmarks present,
it may be challenging to arbitrarily assign a vertical dimension and
condylar position and accurately record it.
Before one can make any bite record, they must have a goal
in mind. In the case of the single tooth crown, the goal is
generally to restore the crown in harmony with the established
occlusal scheme. This means allowing the existing intercuspal
position to dictate the occlusion without making any alterations
to the vertical dimension or the condylar position. In the case of
the free end or distal extension quadrant, the goal is generally no
alteration of the vertical dimension or condylar position either.
However, when a full arch is being restored at one time, we have
the opportunity to establish any vertical dimension or condylar
position we desire. This topic alone could generate many hours
of discussion. I would like to assume in this article the vertical
dimension has been established in the new provisional and
approved by the patient. Therefore, the provisional restoration
maintains the vertical dimension for the bite record.
The question remains, how can we register a bite when
there are no occlusal anatomical stops remaining due to fullarch
tooth preparation? In this segment I will discuss two techniques
for recording a bite record when a full arch is being
restored with crown and bridge reconstruction.
So many times, our tireless efforts at making a ceramic restoration
look beautiful are wasted because we wind up grinding in the
occlusion and losing the beauty of the occlusal anatomy that our
technician worked so hard to deliver (Fig.1, 2). Despite all of our
efforts to evaluate, diagnose, treatment plan, meticulously remove
decay, bond flawless cores, place perfect finish lines, make perfect
final impressions and deliver the case with finesse, if the final
ceramics do not look great, our efforts may feel wasted.
Critical to an exquisite outcome is the recording of an accurate
final bite record. When no occlusal or vertical stops remain
on the previously existing tooth surfaces or dentistry, the dentist
might feel "lost at sea" or confused about how to register a bite
record that captures the condylar position at the desired occlusal
vertical dimension of the desired definitive reconstruction. I will
describe two clinical techniques to record a bite record when the
entire arch has been prepared.
Technique #1 - Sectional Provisional Method
This technique assumes that the entire arch to be restored has
been prepared and temporized with a fixed provisional restoration.
In the illustrated case, a three-piece sectional provisional
has been fabricated.
Step 1: Remove the provisional, refine your preparations and
initiate soft-tissue retraction protocol (Fig. 3).
Step 2: Verify adequate occlusal and incisal clearance by seating
the posterior provisional sections to check for anterior clearance
(Fig. 4) and then switching; placing the anterior provisional
to check for posterior clearance (Fig. 5). Rehearse this closing
routine and mark the lower incisal contact point to the maxillary
anterior cingulum contact point for future verification.
Step 3: With the anterior provisional restoration seated and
the posterior preparations visible, place a rigid polyvinyl silicone
putty between the posterior prepared segments and the opposing
arch. Have the patient close comfortably through the putty until
the anterior contact is exactly as it was in the rehearsed version.
After setting, the bite record should be trimmed and verified in
the mouth that there are no deflective interferences in the
record. In other words, the patient should be able to close as
though the record isn't even present and repeat the anterior contact
relationship that would be present if the record were not in
the mouth (Fig. 6).
Utilizing the anterior section of the provisional restoration to
act as the stop not only preserves the correct vertical occlusal
dimension, but it allows the condyle to seat uninhibited by posterior
tooth influence. This is similar to any anterior deprogrammer
concept such as the Lucia Jig.
Step 4: The anterior provisional is now removed and the
record is verified without the provisional in place (Fig. 7).
Step 5: A small line of polyvinyl silicone is delivered to the
mandibular teeth and the patient is instructed to close into the
existing posterior record. This should be an unhindered and
unmanipulated closure and I always stress, "gentle closing." I do
not want the patient to overcompress the posterior putty bite
records (Fig. 8).
The sectional bite record is now complete and it is made at
the vertical occlusal dimension and the condylar position dictated
by the corrected and confirmed provisional restorations
that the patient has verified to be comfortable.
It is advisable to schedule a metal framework try-in for full
arch cases. This provides the opportunity to not only verify
the marginal integrity and fit of the casting but also allows for
a verification bite record. This bite record is made with a lightcured
composite anterior bite stop placed on the framework and
acts as an anterior deprogrammer in the exact fashion as the anterior
sectional provisional restoration. The bite stop should be
made on the articulator at the same exact vertical dimension as
the casting was made and should be flat with no incisor indentations. Marking it with articulating paper is advisable and acts as
a verification of repeatable closing during the registration of the
record. A line of polyvinyl silicone bite registration material is
placed on the mandibular teeth and the patient is instructed to
close on the anterior jig. Care is taken to verify contact with the
previously marked closing position (Fig. 9-13).
Step 6: Delivery of the final crown and bridge restoration.
This image is taken after occlusal adjustment and polishing (Fig.
Technique #2 - Vacuuform Method
Certain clinical situations dictate the use of a fixed full arch
splinted provisional restoration. In this instance, sectional provisional
bite records may not be possible and the vacuuform
method might be used. This method utilizes a vacuuform of an
accepted provisional cast.
Step 1: Once the patient reports comfort with the vertical
dimension and condylar position, a vacuuform shim is made
over the accepted provisional cast (Fig. 16).
Step 2: The vacuuform is trimmed, leaving a portion of the
palate as a stop, and is tried in the mouth. This try-in serves to verify
the interdigitation and indexing to the opposing arch (Fig. 17).
Step 3: A polyvinyl silicone bite registration material is
placed inside the vacuuform and seated in the mouth. The
patient is instructed to close gently until the vacuuform is interdigitating
the opposing teeth. Bite registration material is not
placed in the palatal portion of the shim so that a verified seating
to the palate is visible (Fig. 18).
Step 4: Once the bite registration material has set, the
patient is instructed to open and additional bite registration
material is placed on the occlusal surface of the opposing teeth.
The patient is asked to close gently until the teeth interdigitate
again (Fig. 19).
Step 5: The record is trimmed and replaced in the mouth for
verification (Fig. 20).
A challenging aspect of full-arch reconstruction is registering
bite records. This paper presents simple methods for making a
bite record when no occlusal anatomy is present to act as a vertical
and centric stop.