9.record base and wax rim fabrication

1. 9.9.Record Base and Wax Rim FabricationRecord Base and Wax Rim Fabrication
Michael Hamada, DDS andMichael Hamada, DDS and
John Beumer III, DDS, MSJohn Beumer III, DDS, MS
Division of Advanced Prosthodontics, Biomaterials Division of Advanced Prosthodontics, Biomaterials
and Hospital Dentistryand Hospital Dentistry
UCLA School of DentistryUCLA School of Dentistry
This program of instruction is protected by copyright ©. No portion This program of instruction is protected by copyright ©. No portion
of this program of instruction may be reproduced, recorded or of this program of instruction may be reproduced, recorded or
transferred by any means electronic, digital, photographic, mechanical transferred by any means electronic, digital, photographic, mechanical
etc., or by any information storage or retrieval system, without prior etc., or by any information storage or retrieval system, without prior
permission.permission.

2. 8. Boxing Impressions and Making Casts8. Boxing Impressions and Making Casts
John Beumer III, DDS, MSJohn Beumer III, DDS, MS
andand
Robert Duell, DDSRobert Duell, DDS
Division of Advanced Prosthodontics, Division of Advanced Prosthodontics,
Biomaterials and Hospital DentistryBiomaterials and Hospital Dentistry
UCLA School of DentistryUCLA School of Dentistry
This program of instruction is protected by copyright ©. No portion of This program of instruction is protected by copyright ©. No portion of
this program of instruction may be reproduced, recorded or transferred this program of instruction may be reproduced, recorded or transferred
by any means electronic, digital, photographic, mechanical etc., or by by any means electronic, digital, photographic, mechanical etc., or by
any information storage or retrieval system, without prior permission.any information storage or retrieval system, without prior permission.

3. Record Base – An interim denture baseRecord Base – An interim denture base
Used to support wax rimsUsed to support wax rims

4. Record Base – An interim denture baseRecord Base – An interim denture base
• Used for making centric relation recordsUsed for making centric relation records

5. Record Base – An interim denture baseRecord Base – An interim denture base
• Used in making trial denturesUsed in making trial dentures

6. Characteristics of an Ideal Record BaseCharacteristics of an Ideal Record Base
Strength and rigidityStrength and rigidity
Accuracy Accuracy
•The record base should not rock on the castThe record base should not rock on the cast
Smooth, rounded well polished bordersSmooth, rounded well polished borders
Thickness of borders and palate must resemble Thickness of borders and palate must resemble
those of the finished denturesthose of the finished dentures
•Palate must be 1-2 mm thickPalate must be 1-2 mm thick
•Thickness and contour of the denture borders are Thickness and contour of the denture borders are
defined by the land of the master cast. The record base defined by the land of the master cast. The record base
must not extend onto the land of the castmust not extend onto the land of the cast

7. Materials Used for Record BasesMaterials Used for Record Bases
Tray resin Tray resin
Brittle but very accurateBrittle but very accurate
Autopolymerizing acrylic resin Autopolymerizing acrylic resin
Strong but less accurateStrong but less accurate
Light cure resin Light cure resin
Accurate but brittle and expensiveAccurate but brittle and expensive

8. Fabrication of Record Bases and Wax RimsFabrication of Record Bases and Wax Rims
Separating medium
Baseplate wax
Wax spatula
Hanau torch
Hot plate
Cloth polishing wheel
Large camel’s hair brush
Red handle knife
Celluloid mm rule
Bunsen burner
Autopolymerizing acrylic resin
Instruments and MaterialsInstruments and Materials

9. Procedures*Procedures*
Blocking out the Master Casts*
–Undercuts
–Frenum areas
–Rugai
–Irregular surfaces
–Redundant tissue areas Mark areas of block out Mark areas of block out
withwith a red pencila red pencil
Flow a thin layer of wax over the
outlined areas with baseplate wax

10. ProceduresProcedures
Blocking out the master casts
Block out frenum and
other irregularities
Wax should be thin enough to
see through

11. ProceduresProcedures
Blocked out master casts coated with
Alcote tin-foil substitute

12. Maxillary Record Base FabricationMaxillary Record Base Fabrication
Sprinkle-on technique of resin additionSprinkle-on technique of resin addition

13. Maxillary Record Base FabricationMaxillary Record Base Fabrication
Build up labial flange by alternating
polymer and monomer addition

14. Maxillary Record Base FabricationMaxillary Record Base Fabrication
Sprinkle on a thin consistent layer
over the palate

15. Maxillary Record Base FabricationMaxillary Record Base Fabrication
Reinforce the ridge crest to prevent slumpingReinforce the ridge crest to prevent slumping
•Keep the surface moist with Keep the surface moist with
monomer to prevent porositymonomer to prevent porosity
•Keep ridge lap areas thin to Keep ridge lap areas thin to
facilitate tooth placementfacilitate tooth placement

16. Mandibular Record Base FabricationMandibular Record Base Fabrication
Manipulate the cast to prevent slumping
Build up the flanges

17. Mandibular Record Base FabricationMandibular Record Base Fabrication
Reinforce the lingual portion of
the flange and ridge crest

18. Record Base PolymerizationRecord Base Polymerization
Process acrylic resin in Pressure Pot
–20 psi
–110 degrees water
–10 to 15 minutes
In absence of a pressure pot, place casts
under an over-turned rubber mixing bowl

19. Record Base PreparationRecord Base Preparation
Then, gently pry the record bases
from the master cast
Soak the polymerized record base
and casts in hot water to soften the
block-out wax

20. Record Base PreparationRecord Base Preparation
Remove wax which may prevent seating of record base from
tissue surface
Gently remove all block-out
wax from master cast
without damaging surface

21. Record Base Preparation MaxillaRecord Base Preparation Maxilla
Areas requiring modification Areas requiring modification
on unfinished record baseson unfinished record bases
Land
FlashFlash

22. Record Base Preparation - MaxillaRecord Base Preparation - Maxilla
Trim excess flash

23. Trim the excess acrylic resin Trim the excess acrylic resin
that extends onto the land of that extends onto the land of
the cast (flash) as shownthe cast (flash) as shown herehere..
Note: The only portion of the record base that is highly polished is the
periphery.
Record Base Preparation - MandibleRecord Base Preparation - Mandible

24. Record Base PreparationRecord Base Preparation
Thin ridge lap portion
of denture base Ridge Lap portion Ridge Lap portion
must be thin must be thin
enough to enough to
accommodate the accommodate the
anterior teethanterior teeth

25. Record Base Contouring/FinishingRecord Base Contouring/Finishing
Palate should be consistent 1-2mm thick to facilitate
speech. Thick record bases may also precipitate gagging.
Pumice the oral (tongue) side of the palate and
flanges for patient comfort

26. Thick maxillary record Thick maxillary record
bases and convex contours bases and convex contours
of mandibular record of mandibular record
bases impinge upon the bases impinge upon the
tongue space and prevent tongue space and prevent
the patient from articulating the patient from articulating
speech sounds in a normal speech sounds in a normal
fashionfashion. .
ResultResult – vertical dimension of occlusion and centric – vertical dimension of occlusion and centric
relation records made from such record bases may be relation records made from such record bases may be
inaccurate.inaccurate.
The “s” sound is particularly The “s” sound is particularly
useful when determining the useful when determining the
vertical dimension of occlusionvertical dimension of occlusion
Patient in the “S” positionPatient in the “S” position

27. Completed Record Bases ChecklistCompleted Record Bases Checklist


Palate should be consistent 1-2 mm thick and well adapted
Lingual of ridge of mandible reinforced but concave
Retromolar pad area covered
Thin areas labial to ridge
Roughened ridge areas

28. Completed Record Bases ChecklistCompleted Record Bases Checklist
No porosity or voids on tissue No porosity or voids on tissue
surfacesurface
Flanges smooth and roundedFlanges smooth and rounded
Tissue surfaces well adapted

29. Completed Record Bases ChecklistCompleted Record Bases Checklist
No excess flash on land area
of master casts
Record bases do not rock
on master casts and are
reasonably retentive

30. Wax Occlusion Rims - PurposeWax Occlusion Rims - Purpose
Serve as a means of transfer of face bow Serve as a means of transfer of face bow
transfer recordstransfer records
Aid in orientation of the incisors and the Aid in orientation of the incisors and the
occlusal plane when properly contouredocclusal plane when properly contoured
Aid in developing contours of the lips and Aid in developing contours of the lips and
cheek when properly contouredcheek when properly contoured
Used in developing the vertical dimension Used in developing the vertical dimension
of occlusionof occlusion
Used in making tentative centric relation Used in making tentative centric relation
recordsrecords
Serve as a general aid in selection of teethServe as a general aid in selection of teeth

31. Instruments and MaterialsInstruments and Materials
•Baseplate waxBaseplate wax
•Kingsly scraperKingsly scraper
•Wax spatulaWax spatula
•Occlusal plane former Occlusal plane former
(hot plate(hot plate)

32. a)a)Place maxillary record base on Place maxillary record base on
the cast.the cast.
b)b)Heat a sheet of baseplate wax in Heat a sheet of baseplate wax in
the Bunsen burner until the wax the Bunsen burner until the wax
is very pliable.is very pliable.
c)c)Roll the wax into long tube.Roll the wax into long tube.
d)d)Starting at the tuberosity, press Starting at the tuberosity, press
the roll of wax against the crest the roll of wax against the crest
of the ridge.of the ridge.
e)e)Seal the wax to the record base Seal the wax to the record base
with a hot wax spatula. If with a hot wax spatula. If
necessary,necessary, fill in the voids with fill in the voids with
additional wax.additional wax.
Technical ProceduresTechnical Procedures

33. f) Heat the occlusal plane former in a f) Heat the occlusal plane former in a
flame and carefully form the occlusal flame and carefully form the occlusal
aspect of the rim. Catch the melted wax in aspect of the rim. Catch the melted wax in
a paper towel.a paper towel.
g) Form the buccal and labial contours g) Form the buccal and labial contours
with the hot plate in a similar manner. If with the hot plate in a similar manner. If
there are voids fill them with wax and there are voids fill them with wax and
repeat the process.repeat the process.
Technical ProceduresTechnical Procedures

34. Maxillary Wax Rim Check ListMaxillary Wax Rim Check List
The occlusal portion of the rim
should have the following
thickness
a) Molar region - 8 mm
b) Premolar region - 6 mm
c) Anterior region - 3 mm
As viewed from the lateral
perspective the rim should project
anteriorly to just beyond the outer
edge of the land of the cast.
Lingual contours must not impinge
on the tongue space.
Anterior
region
Posterior
region

35. Maxillary Wax Rim Check ListMaxillary Wax Rim Check List
The labial and lingual surfaces
must be smooth and free of voids
The posterior section of the rim
should be tapered to avoid the
retromolar pad
The curvature of the anterior
portion must simulate the
curvature of the edentulous arch

36. The mandibular wax rim is The mandibular wax rim is
fabricated in a similar fabricated in a similar
manner, however, the rim manner, however, the rim
should be centered over the should be centered over the
crest of the ridge.crest of the ridge.
Lingual contours must not Lingual contours must not
impinge on the tongue space.impinge on the tongue space.
Mandibular Wax RimMandibular Wax Rim

37. Completed Wax RimsCompleted Wax Rims

38. a.a. Face Bow Transfer RecordFace Bow Transfer Record
The face bow bite fork is The face bow bite fork is
attached to the wax rim attached to the wax rim
and this apparatus is and this apparatus is
positioned intra-orally. The positioned intra-orally. The
face bow apparatus is face bow apparatus is
attached and appropriately attached and appropriately
adjusted and transferred to adjusted and transferred to
the articulator, permittingthe articulator, permitting
proper mounting of the proper mounting of the
maxillary cast on the upper maxillary cast on the upper
member of the articulatormember of the articulator..

39. a. Facebow Transfer Recorda. Facebow Transfer Record
The mounting is carefully The mounting is carefully
smoothed and sanded. smoothed and sanded.
When you are finished When you are finished allall
your mountings must look your mountings must look
like this one.like this one.

40. b.b. Determine Incisor Position and Occlusal PlaneDetermine Incisor Position and Occlusal Plane
Record base and wax rim is Record base and wax rim is
placed into position and a placed into position and a “Fox”“Fox”
occlusal plane can be used to occlusal plane can be used to
verify the proper level and verify the proper level and
angulation of the occlusal plane.angulation of the occlusal plane.
If the wax rim does not conform If the wax rim does not conform
to the landmarks indicating the to the landmarks indicating the
proper plane of occlusion proper plane of occlusion
(Camper’s plane) the was rim is (Camper’s plane) the was rim is
altered until it does conform.altered until it does conform.

41. When the wax rim is ideally contoured and mounted and the lower cast When the wax rim is ideally contoured and mounted and the lower cast
mounted on the on the articulator with a centric relation record, the mounted on the on the articulator with a centric relation record, the
plane of occlusion is readily seen.plane of occlusion is readily seen.
The three determinants of the occlusal plane are readily seen:
b)The incisal edge of the central incisor
c)The middle third of the retromolar pads bilaterally
b. Determine Incisor Position and Occlusal Planeb. Determine Incisor Position and Occlusal Plane

42. cc.. Aid in developing contour of the lips and cheeksAid in developing contour of the lips and cheeks..
Wax rim is contoured with
the rim former until the
desired lip and cheek
contours are developed

43. d. Determine the Proper Vertical Dimension of d. Determine the Proper Vertical Dimension of
OcclusionOcclusion
The wax rims aid the clinician in determining
the proper vertical dimension of occlusion.

44. Wax rims are used as an aid to determine Wax rims are used as an aid to determine
the proper vertical dimension of occlusion the proper vertical dimension of occlusion
and making centric relation records and and making centric relation records and
transferring them to the articulator.transferring them to the articulator.
e. Used to Make Centric Relation Recordse. Used to Make Centric Relation Records

45. ee.. Used to Make Centric Relation RecordsUsed to Make Centric Relation Records
“VDR”
“VDO”

VDO = The length of the
face when the teeth are in
contact and the mandible
or the teeth are in centric
relation

46. f.f. Serves as a General Aid in Tooth SelectionServes as a General Aid in Tooth Selection
The position of the corners of the mouth are marked on the
wax rims and the distance between these two marks can
serve as a guide to tooth selection.

47. A wax rim properly contoured in the anterior region A wax rim properly contoured in the anterior region
(arrows) aids in positioning the anterior teeth.(arrows) aids in positioning the anterior teeth.
Anterior maxillary teeth are arranged according to the Anterior maxillary teeth are arranged according to the
labial contours developed in the patient.labial contours developed in the patient.
f. Maxillary Record Base and Wax Rimf. Maxillary Record Base and Wax Rim