Removable Prosthodontic Calibration

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Removable Prosthodontic Calibration
Dr. William G. Golden Clinical Associate
Professor and Prosthodontist Director of
Removable Prosthodontics
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Increased Vertical Dimension
I think everyone here would recognize these two
examples as an open bite (increased vertical
dimension).
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Increased Vertical Dimension
But how about these?
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Increased Vertical Dimension
How do you correct the dentures without starting
over?

• Refine the fit of the denture bases to the mouth
  with PIP.
• Verify the correctness of the vertical position
  of the upper anterior teeth.
• If the vertical position of these front teeth
  are too long, adjust the maxillary anterior teeth
  by selective grinding until the fricative sounds
  are clear and distinct.

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Increased Vertical Dimension
How do you correct the dentures without starting
over?

• Remount the casts by using a new facebow record
  and centric relation record.
• Intraorally, reduce the maxillary anterior
  teeth until the wet/dry line of the lower lip
  contacts their incisal edges.
• Replace the maxillary back on the articulator and
  raise the guide pin.
• Reduce the occlusion of the maxillary posterior
  teeth until the maxillary incisors meet with the
  mandibular incisors in protrusive.
• Evaluate the VDO of the dentures in the mouth
  and make another CR record.

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Increased Vertical Dimension
How do you correct the dentures without starting
over?

• Remount the mandibular remount cast.
• Remove all maxillary teeth from the denture
  base.
• Replace the denture base on the maxillary
  remount cast.
• Set a new set of teeth on the maxillary denture
  base.
• Perform a wax try-in of teeth.
• Intraorally, evaluate the VDO of the dentures
  and the function of the teeth.

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Increased Vertical Dimension
How do you correct the dentures without starting
over?

• Box and pour the denture as if it were a final
  impression.
• Trim the cast with the denture in place and
  send it to the lab for processing, clearly
  stating in the lab prescription the denture base
  is to be retained as the denture base of the
  final denture.
• Have the lab finish and polish the denture and
  return it ready to insert in the patients mouth.
• Evaluate and treat it as you would the original
  denture.

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Vita shades

• Only two of the Bioform shades correspond with
  the Vita shades - shades 59 69, therefore,
  please do not request them.
• We do not provide teeth for complete dentures
  made in the predoctoral clinic that are the
  brands made for these shades.

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10 20 Degree Teeth

• These are not available for use in complete
  dentures in the predoctoral clinics.
• Students are not trained to use them and it
  just adds more confusion to their limited
  understanding of complete dentures.
• Often, when students complete an occlusal
  equilibration, the anatomical teeth resemble 10
  20-degree teeth anyway.

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Porcelain Teeth
We do not encourage the use of porcelain teeth
in the predoctoral clinics because they are very
hard to equilibrate to establish bilaterally
balanced occlusion.
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Anatomic teeth for Class II Class III patients?

• These dont allow the freedom of movement
  needed for a Class II patient.
• There are very difficult to set in a crossbite
  situation as is often the case with a Class III
  patient.
• Unstable dentures cause sore spots.

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Zero-degree teeth set with a compensating curve?

• We set zero-degree teeth in a monoplane
  occlusion. If there is no vertical overlap of
  the anterior teeth, what is the need for a
  compensating curve?
• Balancing ramps?

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Anterior guidance with zero-degree teeth?
There should be no anterior guidance/interference
in any complete denture. This causes
instability of the denture, leading to discomfort
and broken/dislodged teeth.
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Patients expecting a reline at six month mark?

• Option of reline presented up front.
• Patient insisting on reline instead of new
  denture.
• Interim prosthesis.
• Erroneous billing.
• Patient dissatisfaction with the fit.
• Patients not wanting to pay for the tissue
  conditioner relines.

If these interim dentures are determined to be
suitable for relining, they are then reclassified
as immediate complete dentures and relined. The
code for the denture must be changed at that time
and the patients account will be changed to
reflect the adjustment and the patient will be
charged the difference in cost between the
interim complete denture and the immediate
complete denture. The patient will also be billed
for a reline. The student will get credit for a
reline.
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Mandibular posterior teeth not set over the ridge.

• Mandibular posterior teeth must be set over the
  ridge.
• Anatomical mandibular posterior teeth must be
  set with the buccal cusps over the middle of the
  mandibular ridge.
• Zero-degree mandibular posterior teeth are set
  with the central fossae over the middle of the
  mandibular ridge.
• Lines must be drawn on the casts to indicate
  the middle of the ridge.
• Lines must be drawn on the casts to indicate
  the depth of the anterior vestibule.

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Clinical remount is not necessary?

• Clinical remounts are always necessary for
  complete dentures.
• Increased stability
• Increased retention
• Increased function
• Increased patient satisfaction

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Erroneous Patient Remounts

• Casts not mounted in CR.
• Poor centric relation record not at the
  first point of occlusal contact, not one piece.
• Poor quality facebow transfer/remount index
• Inaccurate or no protrusive record.
• Horizontal condylar guidance is not set
  properly.

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Erroneous Patient Remounts

• Maxillary dentures are not flat-surfaced (if a
  monoplane occlusion is used.)
• Monoplane teeth - guidance setting not
  established parallel to the occlusal plane.
• Mandibular occlusal plane not flat and in
  intimate contact with the maxillary occlusal
  plane.
• Poor quality remount casts.
• Instructor did not thoroughly evaluate the
  remount.

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Safety Infection Control Regulations

• Faculty not enforcing them.
• Faculty not following them.
• Students not properly attired.
• Patient not wearing safety glasses.
• Student not wearing safety glasses.
• Children in the area.
• Student blowing on dentures with the mouth.
• Student not wearing protective mask properly.

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Safety Infection Control Regulations

• Flames too near to hand disinfectant
  dispensers.
• Students not keeping area clean, especially the
  sink area.
• Students not disinfecting the impressions.
• Patient not wearing a patient napkin.
• Student using a non-sterile instrument to mark
  the midline on the wax rim.
• Students using improper knife or using it
  improperly.

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Guide pin is not set at zero.

• Initial mounting - not set on zero.
• Remounting - not set on zero.
• Cannot assume the setting is correct.
• Student used articulator for another case.
• Guide table was not set so the pin was
  contacting the axis of rotation mark and the
  incisal guide angle was changed.

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The condylar guidance is set wrong for the teeth.

• Student used the articulator for another case
  and forgot to change the setting.
• Student didnt know what the correct setting
  was.
• The condylar lock nut is loose.

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Master casts/final impressions have no hamular
notches.

• Cast finished down too close in the distal.
• Hamular notch was not captured in the
  impression.
• Student did not box the impression properly and
  leave adequate room for the land area.

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Master casts/final impressions have no retromolar
pads.

• Cast finished down too close in the distal.
• Retromolar pad was not captured in the
  impression.
• Student did not box the impression properly and
  leave adequate room for the land area.
• Retromolar pad area was reduced because it
  interfered with protrusive or lateral movements.
  (Occlusal plane must be at least 2/3 of the way
  up the highest retromolar pad.)
• Cast would not fit in the processing flask.

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Master casts/final impressions with excessive
width in the vestibular areas.

• Compound was not scraped/trimmed adequately.
• The tray was not reduced enough initially.
• Excessive blockout of undercuts.
• Mandibular trays without finger rests.
• Inadequate border molding.
• Student chilled the compound before placing the
  tray in the mouth.

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Trays with improper handles
Trays must fit the mouth have handles that will
not interfere with the border molding process and
still allow for easy placement and removal.

• Handle did not come off crest of ridge.
• Handle was too short to grasp.
• Handle was made at right angle or drooping down
  (prevents lip from being raised or lowered
  completely in that area).
• Mandibular tray without finger rests.

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Trays that are under-reduced for the impression.

• Overextended impressions in the vestibular
  area.
• Complete dentures (particularly the lower) with
  excessive flange length.
• Frenular notches are not present.

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Casts with insufficient or no land area

• Cast finished down too close in the distal.
• Student did not box the impression properly and
  leave adequate room for the land area.

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Master casts that are too thick or too thin.

• Impression was not properly boxed poured.
• Thickness of the cast base was over-reduced or
  under-reduced.
• Student tried to make up for thin cast by
  pouring a second pour on the base.
• Student did not box and pour the cast but used
  the double-pour method.

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Final impressions made of materials other than
polysulfide impression material.

• We use a low viscosity (light-body, injection
  type) wash of polysulfide impression material to
  make our final impression for a complete denture.
• Easier to remove from a cast without breaking
  or otherwise marring the cast.

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Improper baseplates/improper blockout destroyed
casts.

• Insufficient blockout.
• Wrong separating medium was used.
• Trays were under-reduced.
• Casts were not soaked in hot water before
  removing the tray/impression.
• Students focused on a tight fit/lots of suction
  with baseplates rather than on protecting the
  casts.

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The end