You say you want to increase your production in 2014 and
create a niche practice that will stand alone from all of the other
practices in your area? Top consultants, practice management
gurus and even organizations recommend that dentists map out
their continuing education plans and goals in the beginning of
the year. Likewise, the New Year often brings out the business
man/woman in all of us to budget the year’s marketing expenses.
If your goals are to add more procedures to your existing patient
pool, become more predictable in a procedure that many dentists
dislike and to invest a little money marketing in an area very
few dentists target – then I challenge you to revisit the art of
removable prosthodontics.
It is estimated that 23 million people in the U.S. are fully
edentulous, while an additional 15 million are edentulous in
one arch.1 Currently, that is an estimated 61 million complete
dentures in the U.S. If 10 percent of these patients have a new
denture/dentures fabricated each year and the average dentist
charges $1,400 per denture, this results in an estimated 8.5 billion
dollars being spent each year on full dentures. Still think
dentures are dead? Consider the fact that the average gross of all
Hollywood movies in one year is approximately 9 billion dollars,
does targeting full denture patients now seem more worthwhile?
I know what you are saying, “But John, I hate fabricating
dentures! The unpredictable fit returned from the lab, the neverending adjustment appointments and, quite frankly, the aesthetics
are marginal at best.” In reply, I ask you, besides dental
school, what advanced training in removable prosthodontics
have you had? Grab a cup of coffee, turn off the TV – let’s get
ready to love dentures!
Starting with a Healthy Foundation
If your patient has unhealthy tissue from wearing an old,
poor-fitting prosthetic, it would behoove you to begin with
a tissue-conditioning process. This could take several weeks.
Products like Lynal or Hydrocast work great for this. Start by
placing a thin layer of pressure-indicating paste on the inside of
one of the dentures, completely covering the intaglio of the denture.
Adjust any “show through” spots of acrylic until you have
a complete thin layer of PIP. Once this is complete, you are
ready to reline the denture(s) with the tissue-conditioning material.
When asking the patient to close into occlusion, make sure
cotton rolls are used to provide uniform contact on both sides of
the denture.
Once the initial set of the tissue conditioner has taken place
(follow manufacturers recommendations) it is now time to
adjust the occlusion. Verify there are simultaneous, bilateral contacts
in MIP and that the occlusion is balanced in excursions.
Have the patient return in 48 hours to evaluate the fit of the
denture. Where the tissue conditioner is thin or is absent, adjust
the denture acrylic there and add more tissue conditioner (the
same process you did with the PIP). This may take several visits
until the tissue conditioner has a uniform thickness, the denture
fits well and the tissue is no longer edematous or erythematous.
Once the tissue is healthy, we are ready to begin the new denture
process.
First Appointment (approximately 45-60 minutes)
Unlike the denture fabrication process you were taught in
dental school, the “Smile Designed Dentures” process requires a
little more time on your first visit. Don’t worry, a little extra time
spent here will save you plenty of time in the following two visits,
as well as reduce your post-op visits. In my experience, this
is time well spent! The instruments shown in this article (except
the gothic arch tracer) are available in the Removable Smile
Design Kit by Ivoclar Vivadent.
Step 1: The Impression
The final impression is considered one of the most important
steps in denture fabrication. There are plenty of great
impression materials and systems on the market. The Accu-
Dent I System (Fig. 1) from Ivoclar Vivadent is an irreversible
hydrocolloid that offers a truly hydrophilic impression material.
This material must be poured within eight minutes,
should not be wrapped in wet paper towels (like you were
taught in school) and the stone should be mixed with a Vacumixer
after carefully weighing out and measuring the stone and
water. If you have the equipment in your office to do so, I
would highly recommend this material. If you do not have the
capabilities of following this protocol, then I would consider
using VPS as your impression material and allowing the lab to
pour the models.
Polyvinyl Siloxane (VPS) – (Virtual XD: Ivoclar Vivadent)
– can be used to “customize” your impression tray and provide
an excellent retentive impression. Of your hour-long initial
visit, expect to spend roughly 45 minutes on the following
impression technique. Your initial step in the impression technique
is to select the proper tray size. If the patient is currently
edentulous, use the existing denture to measure the distance
between the maxillary tuberosities with a measuring gauge
(Fig. 2). Use this measurement to select a tray that demonstrates
the same position of the tuberosities. Make sure you verify the
fit intra-orally prior to starting the impression. Retractors such
as the “See More Retractors” (DENTSLPY) or “OptraGate”
(Ivoclar Vivadent) are used to aid in the impression-taking
process and are removed following placement of the impression
tray. Prior to each step, the retractors are repositioned (Fig. 3).
Once selected, the second step in the process is to add “tissue stops” by injecting three small areas on the tray (bilaterally over
the ridge and the hard palate) with heavy body impression material
(Fig 3). Allow this to set fully prior to removal.
Next, start the border molding process. Once again, heavy
body impression material is injected, starting from the side of
the maxillary tuberosity and continuing to the canine area. Care
is given to avoid having impression material go behind the
tuberosity into the hamular notch area just yet (Fig. 4). Place the
impression tray, remove the retractors from the patient’s mouth,
and border mold this side of the impression by actively moving
the patient’s cheek in an anterior, posterior and downward
motion (Fig. 5). Continue the border molding process by next
border molding the anterior segment only (Fig. 6), and then the
opposite side, taking action to activate the labial frenum in the
anterior and posterior regions each time.
Once the border molding is complete, inspect the tray for
areas of show-through. Adjust these areas with an acrylic bur to
remove the over-extended areas or areas of the tray on the internal
aspect that show through the impression. Complete the
impression by adding light body impression material to the tray
and placing it into the patient’s mouth, starting with the posterior
segment and seating toward the anterior. Repeat the border
molding process on both sides bilaterally, then the anterior segment.
Finish the posterior palatal seal portion of the impression
by first holding the patient’s nose and asking them to blow hard
through it. Next, ask the patient to open as wide as possible,
close half way down, and then repeat opening and closing a second
time. This action will capture the hamular frenum in the
light body impression material and is the reason why this area
was not initially border molded with the heavy body material.
Once set, your maxillary impression is now complete (Fig. 8).
Repeat the same process for the lower denture by border
molding the labial segments first and finishing off on the lingual.
A trick to prevent the lower denture from dislodging in
functional movements is to have the patient close against your
fingers, stick the tongue out and move it from one corner of
the lip to the other when bordering molding the lingual segments.
This process should be repeated once you add the light
body impression material to complete the full impression. This
action will prevent over-extension onto the mylohyoid area,
which can act as a sling when the denture covers it.
Step 2: Smile Design Tools
Once the impressions are completed, order a custom wax rim
length by measuring the length of the maxillary lip and the current
denture teeth set up. These steps take approximately five minutes
of extra time on the initial visit but save a lot of time on your
second visit from having to make large adjustments to a stock wax
rim length. The instruments used for this are the papillameter
(Fig. 9) and alma gauge (Fig. 10). The papillameter is placed under the patient’s lip and against the incisive papilla, allowing you
to accommodate for the varying maxillary lip lengths. The patient’s
lip is measured at rest to determine the proper vertical position of
the wax rim (Figs. 11a & b). Discuss with the patient how much
tooth structure the patient would like to display at rest; the measurement
can be adjusted accordingly to fit the patient’s needs.
When ordering the wax rim, I suggest allowing for 1-2mm at rest.
The alma gauge allows you to measure both the vertical and
horizontal position of the incisal edges from the incisive papilla of
the existing denture. The existing denture can be judged for its cosmetic
appearance. Wax or flowable composite can be added to the
old denture as a “cosmetic mock-up” to test the appearance of the
planned final denture. These new lengths can then be measured by
placing the denture on the gauge and depressing the plunger into
the dentures incisal papilla area. The vertical and horizontal measurements
are recorded and transferred to the lab. This will become
the length, as well as horizontal thickness, of the wax rim ordered.
The final 10 minutes of your first visit are to use the centric tray
(Fig. 13) to record an arbitrary bite relationship in fully edentulous
patients. This can be taken at the patient’s existing VDO and will
facilitate the lab in the proper mounting of the gothic arch
tracer/centric recording device for your next visit. Gauze is used to
line the centric tray to facilitate removal of the putty once the lab
has mounted the study models. Putty is hand-mixed and placed
inside the maxillary and mandibular components of the tray, and
then placed in the patient’s mouth while the patient is asked to close
to a reasonable proximity of the existing denture VDO (Fig. 14).
Once the putty is set, the impression is removed (Fig. 15) and sent
to the lab with the full-arch impressions, papillameter, and alma
gauge readings for design of the wax rim and initial smile design.
Second Appointment – Enhanced Wax Relations
(approximately 30-45 minutes)
Since the wax rim should be near the perfect length and horizontal
positions, this visit is significantly shorter and less involved
than the traditional denture fabrication process. The time saved
here in adjusting the wax rim allows us to record the patient’s
VDO and centric relation position with the use of the gothic arch
tracer/centric recording device.
Step 1
The first step in this visit is to evaluate the wax rim length and
make any necessary adjustments to the vertical and horizontal positions
(Fig. 16). Marks are scribed into the wax rim for the lip at rest
position, high smile line and midline (Fig. 17). The wax rim former
(Fig. 18) is designed to facilitate the development of the occlusal
plane once the desired incisal edge position has been achieved.
Ensuring parallelism between the maxillary and mandibular rims is
essential for a correct bite registration, if the gothic arch tracer is not
to be used. When aligning the rims to Camper’s plane, it is particularly
important to be able to melt the rims uniformly. The ledge of
the rim former fits precisely into the hamular notches on the maxillary
cast. The hamular notches are always parallel to one another and
to the midlevel of the face;4,5 it is important to have your base plate impressions detailed enough and free of distortion in these areas.
The 5mm ledge present on the rim former ensures that when the
maxillary wax rim is melted down to the desired incisal edge position
(chosen by using the papillameter and marked on the wax rim)
(Fig. 19), the occlusal plane will be uniform on both right and left
sides and should be parallel to Camper’s plane. Typically, I use the
lower base plate to record the incisal edge position of the mandibular
teeth equal to the lower lip line at rest.
Step 2
The second step of this visit is to confirm that the wax rim is
parallel to the patient’s interpupillary line and that a cant does not
exist. This can be accomplished two ways. The first is to use the
occlusal plane that is present in the Smile Design Kit (Fig. 20). The
second is to use a Kois Facial Analyzer. If the interpupillary line and
horizontal plane do not match, you have the option of either correcting
the wax rim or using VPS bite registration material on the
occlusal plane to compensate for the irregularity. The VPS record
should be sent with the wax rim to the lab for corrective mounting.
Step 3
The third step is to record the patient’s vertical dimension of
occlusion and centric relation position. The calipers in the Smile
Design Kit (Fig. 14) can be used to replicate the same VDO as the
patient’s existing dentures or aid in selection of an increase. There
are several gothic arch tracers/centric recorders on the market
including the Gnathometer (Ivoclar Vivadent), Y&M Intraoral
Tracer (Edmonds Dental Lab), Intra-Oral Establisher (Massad-
Davis) or Coble Balancer to help record the patient’s centric relation
position. To facilitate in this process, it is sometimes easier to
have the lab fabricate a second set of base plates with the recorder
mounted on it without the wax rims. Recording the centric relation
position is probably the single-most important step in denture
construction, second only to the impression technique. It is ideal to
first adjust the vertical component of the recorder to match the
patient’s desired VDO. Depending on what tracer you are using,
you may either want to paint the strike plate with magic marker or
use articulating paper to mark the strike plate. (It is best to follow
manufacturers instructions on which one would be best.)
Once properly marked, the patient is instructed to slide the
mandible forward, backward, and into left and right lateral excursions.
The resulting marks on the strike plate should resemble an
arrow; the tip of this arrow is the patient’s CR position (Fig. 21).
The center of the centric pin receiver is then placed over the point
of the arrow and luted to the strike plate with sticky wax or green
stick compound. The base plate is then placed back in the patient’s
mouth and the patient is guided until the pin goes into the hole in
the centric receiver. At this time, use hard bite registration material,
Futar D (Kettenbach), to secure the baseplates together (Fig. 22).
Step 4
The last step on the wax-relations visit is to select the tooth size,
mold and shade with the use of the Facial Meter (Fig. 23). The cosmetic
outcome of your denture is highly reliant on tooth selection
and custom processing of the denture base by your laboratory.
Depending on your case fee, several denture tooth options present
themselves from basic to premium in aesthetics and function. The
Phonares II by Ivoclar Vivadent are an excellent option in the premium
range. Tooth selection is facilitated by the interalar distance
as measured by the Facial Meter. Teeth are offered in small, medium
or large molds with choice of bold or soft forms, each offered in long
or short for age appropriation.7 Typically, the posterior setup I most
often use is Lingualized Balanced for the cosmetic appearances
resembling natural teeth and the functional ease of equilibration.
Third Appointment – Wax Try-in (approximately
15-30 minutes)
With all the extra steps you have taken in the previous two visits,
the “wax try-in” visit becomes a simple confirmation of the
patient’s smile, occlusion and selection of processing shade. This
visit gives the patient a chance to preview his or her smile and make
any changes from the desired plan. Many patients today are selecting
a Phonares II form and setup that allows for a more natural
appearance. This can be accomplished with rotation of the lateral
incisors, placing the premolars slightly off the facial plane from the
canine to the molar, mimicking a slight decrease in the buccal corridor
or angling one of the canines so more of the distal aspect of
the tooth shows over the other. Rather than spending time making
adjustments chairside, corrections are usually done so with photography
to communicate the desired changes to the lab. However, if
you prefer to make the changes chairside, scheduling a 30-minute
try-in will ensure enough time to make any last-minute changes to
the position of teeth as deemed necessary.
The final step in the denture process is to select the shade and
type of processing for the lab to finish the denture. Ivocap and the
new IvoBase pressed processing have long been established as the
premiere processing for denture-base finishing. If you have been
unhappy with the fit of your dentures, despite having a very retentive
impression on your first visit, inaccuracy in processing maybe
the cause of your problems. For this reason, I recommend you have
a discussion with your lab as to whether it is utilizing a cold cure or
pressed processing system. Once your processing shade has been
chosen (Fig. 25), your dentures are ready for processing!
Delivery Day (approximately 30 minutes)
It is finally here, delivery day! It is normal to have to adjust the
dentures for ease of insertion and removal. Once these sore spots
are adjusted, the occlusion can be confirmed. The dentures
should have simultaneous bilateral contact into closure, as well as
have simultaneous contacts in excursions. As a rule of thumb,
when the patient returns for post-op visits, adjustments are only
made to the internal aspect of the denture if the patient states that
the offending area hurts during insertion or removal of the denture.
Otherwise, if the denture does not hurt to insert or remove,
but becomes sore after a period of use, the occlusion should be
considered the cause.
Following this detailed protocol, I am sure you will find that
your patients will be not only pleased with the cosmetic outcome
of their prosthesis, but also require less post-insertion adjustments.
Our population is aging and edentulism isn’t going away, as we
once thought it would. More and more patients are shying away
from the coupon dentures that are available and are searching for
dentists who can provide them with high quality prosthetics. Forget
your bad experiences or what you learned in dental school! With a
streamlined, tried-and-true system, dentures can be fun, rewarding
and profitable
References
- Summary Health Statistics for U.S. Adults: National Health Interview Survey, 2009, tables 11, 12. U.S. Department of Health and
Human Services
- J Prosthodont. 2008 Oct;17(7):572-5. Epub 2008 Aug 26. Occlusal plane orientation: a statistical and clinical
analysis in different clinical situations. Jayachandran S, Ramachandran CR, Varghese R
- J Oral Rehabil. 2007 Feb;34(2):136-40.Three-dimensional analysis of the occlusal plane related to the hamular-
incisive-papilla occlusal plane in young adults. Fu PS, Hung CC, Hong JM, Wang JC.
- J Prosthet Dent. 2009 Sep;102(3):194-6. Incisive papilla line as a guide to predict maxillary anterior tooth display. Oh WS, Hansen C.
- J Prosthet Dent. 2007 Oct;98(4):312-8. The three-dimensional relationship on a virtual model between the maxillary anterior teeth and incisive papilla. Park YS, Lee SP, Paik KS.
- J Indian Dent Assoc. 1984 Nov;56(11):425-8.An investigation into the distance between incisive papilla and
incisal edge of maxillary central incisor. Kharat DU, Madan RS.
- J Ayub Med Coll Abbottabad. 2009 Oct-Dec;21(4):125-8. Comparison of distance between maxillary central
incisors and incisive papilla in dentate individuals with different arch forms. Zia M, Azad AA, Ahmed S.
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