Processing Ideal denture base material: No trial packing

1
Processing

• Ideal denture base material
• No trial packing needed
• Good shade match with surrounding tissues
• Dimensionally stable
• Complete polymerization
• Easily polished

2
Processing

• Note Master cast must be recovered from flasking
  for laboratory remount.
• Techniques
• Compression
• Microwave
• Injection

3
Processing Technique

• Compression molding
• Conventional method
• More than 60 years
• Time consuming

4
(No Transcript)
5
(No Transcript)
6
(No Transcript)
7
Master cast

• Mounting (with casts already indexed on the bases)

Trim base of cast to the dimension that
will fit in the processing flask prior to
indexing
8
2
1
3
Split mold

• Denture flask (ejector-type, three piece)
• The drag (bottom)
• The cope (middle)
• The cap (thin top)

9
Split mold
10
(No Transcript)
11
(No Transcript)
12
(No Transcript)
13

• Maxillary denture with the index in place and
  embedded in the flask Soap, or a gypsum
  separator, is used between the two pours of
  dental stone in the lower and upper portions of
  the flask.

14
(No Transcript)
15

• The surface of the third layer is left slightly
  rough to hold the fourth investment layer in
• position.
• Tinfoil separating medium is painted on the third
  layer.
• The fourth investment layer is used to fill the
  remainder of the flask. The lid of the flask
• is pressed into place while the investing stone
  is still soft. The flask is set aside for
• min. 1 hr. before the wax elimination.

16
Second pour (upper half of flask)
17
(No Transcript)
18
(No Transcript)
19
(No Transcript)
20
(No Transcript)
21
Flask press
22

• Boil-out
• When the wax and shellac record base are
  completely warmed, the flasks can be opened. The
  teeth remain in the lower portion of the flask .
• The record base is soft and can be easily removed
  in one piece, along with any remaining wax.
• Both flask halves are thoroughly cleaned by
  rinsing with boiling water. The teeth are removed
  and also cleaned with boiling water. Ensure that
  the wax is completely removed by using a
  detergent.

23
(No Transcript)
24
Placed in boiling water for 5 mins to soften the
wax

• Stiff, bladed instrument is used to open the
  flask. Upper portion of the flask is lifted as
• vertically as possible to avoid fracturing the
  investment layers.
• The softened wax is removed from the mold.
  Remaining wax is flushed from the mold
• with a stream of boiling water. The mold is
  then cleaned with a soft brush and a
• powdered detergent. Detergent is removed by
  flushing the mold with clean boiling water.

25
(No Transcript)
26
(No Transcript)
27

• Smooth all sharp edges and create an escape
  groove
• Feathered stone edges must be removed because
  they break off easily and can become embedded in
  the acrylic resin base material. A groove is made
  completely around the master cast for the purpose
  of allowing excess acrylic resin to escape
  (right).
• The surface of the dental stone in both halves of
  the flask is coated with a gypsum separating
  medium. Each tooth is carefully placed in its
  original position. Make under cuts in the acrylic
  resin teeth similar to the diatorics in porcelain
  teeth.

28
(No Transcript)
29
(No Transcript)
30
(No Transcript)
31

• Packing
• Mixing the acrylic resin I and packing the dough
• The autopolymerizing acrylic resin is mixed to a
  kneadable dough according to the manufacturers
  instructions (powder to liquid volume ratio
  usually 31) and placed in the cold flask halves
  in which the denture teeth are positioned.

32
(No Transcript)
33
(No Transcript)
34
(No Transcript)
35

• Trial packing (3000-4500 lbs over the entire
  flask area)
• Use two sheets of cellophane between
• two layers of resin dough to allow
• opening of the flask without pulling
• acrylic resin.
• Trim excess acrylic and flash
• Repeat until no excess is visible
• Final closure of the flask halves is
• accomplished without the intervening
• sheets of cellophne
• Heat cure in water bath with temp. set at
• 160-165F for at least 8 hrs. with constant
• pressure

36
(No Transcript)
37
8 hrs 160-165 F
38
Occlusal correction

• Laboratory Remount
• to eliminate the processing error
• depends on
• Jaw relation technique
• instrumentation

39
Processing Technique

• Microwave System
• (GC America Inc.3737 W. 127th Street, Alsip, IL
  60803)
• Use the split mold technique to form molds
• ACRON MC microwave cured acrylic
• Need special flask
• (resin small metal screws)
• One minute microwaved to soften wax
• Eliminate wax from mold
• Three minute curing in microwave
• Leave 15-20 mins before opening flask
• Less VDO increase??
• Easy to use
• Low water absorption

40
Microwave system

• Three minute curing in microwave
• Fast, easy to use
• Allows more efficient use of time
• Produces denture in short processing time
• Denture repair
• Interim partial

41
Processing Technique

• 3. Injection
• 3.1 Ivocap injection system, Ivoclar, Vivadent,
  Inc, Amherst, NY)
• In Mid 1970
• VDO is more stable compare with conventional
• Flask is closed during the procedure

42
Processing Technique

• 3. Injection
• 3.2 Success System (Dentsply, International, Inc,
  York, PA)
• PMMA Lucitone 199
• 90 PSI, use heat-polymerized resin

43
Success
Flasking or Investing
After Boil out
Flask is closed
Divesting
44
Flask in injecting unit
Insert plastic nozzle
De-flasking
Master cast Recovery
45
Master cast removed from invest material
Finished denture
46
Eclipseä Prosthetic Resin System (Dentsply)

• Light-cured composite resin
• New indirect build-up method for making dentures 
• Flask-free and monomer-free
• Conditioning Oven to warm models and materials
• Melting Pot to prepare and melt Contour Resin
• Electric Spatula to apply Contour Resin
• Hot Air Gun to replace flaming
• Eclipse Processing Unit to polymerize materials
• Resin materials and supplies
• Eclipse Bonding Agent             

47
Dimensional change in CD fabricated by injected
molding and microwave processing. Keenan,
Radford, and Clark. J Prosthet Dent
20038937-44.
48

• Deflasking
• Remove the flasking stone
• The denture can be deflasked as shown without
  damage. The silicone index can be easily removed.
• Denture after deflasking
• Because the denture was carefully waxed and a
  silicone index was used, finishing around the
  teeth can be readily accomplished.

49
(No Transcript)
50

• Remounting and Occlusal Equilibration
• After the dentures have been deflasked they are
  mount ed in the articulator without removing them
  from their casts. Small errors can now be seen
  that occurred during the flasking and
  polymerization procedures. Although there is very
  little shrinkage during autopolymerization,
  occlusal contacts may have been slightly altered.
  For this reason, the first occlusal equilibration
  is performed so that a clear cusp-to-fossa
  relation can be obtained

51

• After all centric contacts are established, the
  eccentric excursions are equilibrated and the
  protrusive and retrusive movements are ground
  free from interferences. The occlusion is then
  refined with carborundum paste. Only now should
  the dentures be separated from the casts.
• Post-processing remount
• The dentures are not yet separated. Dentures and
  master casts are remounted in the articulator.

52
(No Transcript)
53

• Checking the condylar guidances
• The condylar guidances are still set at the
  patients individual condylar path angle.

54

• Equilibrating the occlusion in centric relation
• Premature centric contacts
• Polymerization shrinkage has caused a slight
  shift in the original cusp-to-fossa relations.
  Initial contacts are now premature or deflective,
  and must be selectively eliminated in order to
  restore proper intercuspation.
• Below left The occlusion is corrected with a
  round diamond stone. Avoid grinding the centric
  supporting cusps, which in complete dentures are
  primarily the maxillary palatal cusps and the
  mandibular buccal cusps.

55
(No Transcript)
56
(No Transcript)
57
(No Transcript)
58
(No Transcript)
59
Flasking PackingCuringDeflaskingFinishing
Polishing
60
(No Transcript)
61
(No Transcript)
62
(No Transcript)
63
(No Transcript)
64
(No Transcript)
65
(No Transcript)