
by John Nosti, DMD, FAGD, FACE
The year was 1996; it was my sophomore year in dental
school and the administration took away a portion of our removable
education in favor of hands-on education in oral implantology.
The reason for the change in curriculum was that complete
edentulism was falling in statistics nationwide with more patients
holding on to their teeth longer. It was even stated by a few professors
that traditional full dentures would eventually be a lost art
form, and no longer needed. It is currently estimated that 10 percent
of the U.S. population is edentulous.¹ This number is
expected to grow due to the amount of aging adults in the
United States. Likewise the effect of the economic downturn and
illicit drug use has not been taken into consideration.
From 1996 to 2005, the amount of methamphetamine users
doubled on average in the United States² and in some states that
number quadrupled. In 2003, it was estimated that six percent
of the U.S. population was using methamphetamines.³ In 2010,
while some sources indicate the population using illicit drugs
has decreased; those same sources indicate the users requiring
specialized treatment for a drug abuse problem increased.
No matter how you look at it, dentures will continue to be
an essential part of dentistry. Many practitioners shy away from
removable prosthetics due to the variability of procedures
throughout the fabrication process resulting in an unpredictable
outcome. I have spoken with many doctors who favor traditional
fixed smile design over removable smile design. I will
challenge, that in order to become proficient in fixed smile
designs and full-mouth reconstructions, one must become proficient
in removable prosthetic "reconstructions." With the
addition of some simple tools to your armamentarium, removable
dentures will be an enjoyable and profitable process that
can add to your cosmetic dentistry portfolio.
Figure 1 shows the Smile Design Kit by Ivoclar. The
Papillameter (Figs. 2 & 3) is used to measure the maxillary lip
length by using the fixed landmark of the incisive papilla. By determining the length between the maxillary lip at rest and the
incisive papillae, the lab has an exact measurement to construct
the wax rim or placement of the incisal edge in the wax setup.
Transferring this information to the lab when ordering baseplates
and wax rims allows the lab to custom make the wax rims
and facilitates a faster secondary appointment for wax relations.
The doctor is not left "eye balling" the ideal incisal edge position
and wasting time cutting down a stock wax rim that is 6mm too
long; or worse having to add wax because the rim is too short.
Once the incisal edge position has been located, it can become
much easier to focus on recording the proper midline and high
smile line.
The Wax Rim Former (Fig. 4) 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. When aligning the rims to Campers
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 mid level 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), the occlusal plane will be uniform on both right and
left side, and should be parallel to Campers plane. This
process saves a great deal of chair time and allows the dentist
to be more proficient.
The wax rim former can be used in conjunction with the
Alma gauge (dental gauge) (Fig. 5). This gauge allows you to
measure both vertical (Fig. 6) and horizontal (Fig. 7) position of
the maxillary anteriors from the incisive papillae on an existing
denture or base plate. The average patient's incisal edge is
approximately 8-10mm facial from the incisive papillae.6,7,8 This
allows you to measure the facial extension of the denture rim
from the incisive papillae and make any corrections from both a
visual confirmation with the patient, and a standard approach
chairside. If the patient has an existing set of dentures that he or
she would like duplicated, the arch form can be traced on the
plastic sleeve (Fig. 8) of the Alma gauge and sent to the lab so
that duplication of the arch form can be achieved. The vertical
position of the incisors can also be recorded on the plastic sleeve
so that the lab knows the precise horizontal and vertical position
of the incisors.
The bite plane (Fig. 9) is used to confirm a proper occlusal
plane by using the interpupillary line and Campers plane (the
ala-tragus line). By determining the correct incisal edge position
with help of the papillameter, rim former and bite plane, the
facebow transfer in dentures becomes less important considering
that the wax rim has been perfected to the proper occlusal plane
and incisal edge position. For those wanting to use a facebow
transfer, the Kois Earless Facebow (Fig. 10) can be utilized once
the desired incisal edge position has been achieved. The Kois
Earless Facebow is an excellent tool in communicating and transfer of the maxillary model to the lab for mounting on either
the Panadent or Stratos articulator. This facebow utilizes a
removable mounting plate to record the facial-incisal edge position
of the maxillary central incisors. The average position of the
maxillary central incisor is approximately 100mm from the
condylar axis. There is a vertical component to the facebow to
achieve the facial midline, as well as a horizontal component to
match the interpupillary line and horizontal plane. Once your
wax rim has been set to the ideal incisal position, this facebow
can now be utilized.
Taking the bite relationship and setting up the occlusion on
complete dentures is probably the single most important step in
denture construction. Over the years I have consulted with
many patients who were complaining that their brand new dentures,
constructed in other offices, were ill-fitting. Many times
the only treatment rendered to these patients was to equilibrate
their dentures and correct the improper occlusion. The ideal
way to record a centric bite registration is with a needle-point
tracing technique. I have found the Gnathometer-M by Ivoclar
to be useful in that it allows for both chairside bite registration
technique and functional impression taking if desired. In basic
terms, the Gnathometer consists of a marking pin that fits over
the lower rim and opposes a striking plate that is fixed to the
maxillary rim. The marking pin is adjustable, which allows for
changes to the vertical dimension. The Gnathometer is
mounted to base trays in the laboratory and returned for the
same visit with the wax rims. Once the vertical dimension has
been set with the wax rims, the bite registration can be completed.
If desired, the functional impression can be completed
on the base trays followed by the bite registration. The vertical
dimension on the Gnathometer is adjusted until it is the same
as was established with the wax rims. Once this is completed,
the striking plate is marked with black marker, occlude spray or
wax color (China Marker). The patient is instructed to move the
mandible into protrusive, backward, followed by left and right
lateral excursions (repeat process). The marking screw contacts
the opposing plate, resulting in an arrow formed on the
marking plate. The point of the arrow is equivalent to centric
relation. A fixation device is placed over the point of the arrow
and the upper and lower elements can be fixed together with
bite registration material.

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. Both the Blue Line and
PHONARES by Ivoclar are two excellent options in the premium
and ultra premium range. Tooth selection is facilitated
by the interala distance as measured by the Facial Meter (Fig.
11). 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.9
When restoring a fixed full-mouth rehabilitation the standard
of care is to always work out the aesthetics, occlusion, function,
etc. in temporaries. The thought of preparing rehabilitation
and inserting a mouth full of ceramics without utilizing temporaries
is absurd. So, why then do we do our removable reconstructions
without temporaries?
Are you tired of seeing your patient for 20 post-op adjustments
after the denture has been completed and "searching" for
their sore spots? Have patients ever returned unhappy with the
aesthetics of the denture after they are processed and after they
have approved them at the wax try-in visit? I would strongly
consider your first option of fabricating a diagnostic denture and
utilizing a functional impression technique followed by a final
denture fabrication. This two-denture process will allow you to
make any changes to the aesthetics because the patient is allowed
to "try out their smile," rather than approving their smile
during a 10-minute wax try-in appointment. The recoding of
the functional impression over a period of time allows you to
capture the patient's musculature in motion and function, rather
than relying on a single static impression completed in office.
The second option is to utilize the functional impression
technique in your fabricated denture and reline once the kinks are worked out. When the patient returns for scheduled post-op
visits, the denture acrylic will bleed through the functional
impression material where adjustments are necessary. Many
times your scheduled adjustment visits are prior to the surfacing
of sore spots on the patient. This secondary option relies more
on the occlusion being correct at insert and will most likely
require further equilibration due to the potential increase in vertical
caused by the reline.
Whether your reconstructions are removable or fixed, having
a step-by-step process and the correct tools allow you to be more
proficient, predictable and profitable. With the elimination of
unpredictability the process of denture fabrication becomes a
more enjoyable experience for both the patient and practitioner.
With the aging population increasing in the United States, and
the expected increase in edentulism, higher demands will be
made for high quality removable prosthetics. Some of the most
dramatic "cosmetic makeover" patients, and most appreciative
are those who have undergone removal prosthetic treatment.
References
- Summary Health Statistics for U.S. Adults: National Health Interview Survey, 2009, tables 11, 12. U.S.
Department of Health and Human Services.
- US Department of Health and Human Services, Substance Abuse and Mental Health Services
Administration. 2005 national survey on drug use and health.
- U.S. Department of Health and Human Services, Substance Abuse And Mental Health Services
Administration, Office of Applied Studies. 2003 national survey on drug use and health.
- 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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