Lab procedures in complete denture prosthodontics/ dental education in india

LAB PROCEDURES IN COMPLETE
DENTURE FABRICATION
INDIAN DENTAL ACADEMY
Leader in continuing dental education
www.indiandentalacademy.com

CONTENTS
• Introduction
• Pouring the diagnostic impression & Making the
diagnostic cast
• Pouring the primary impression Making the primary cast
• Fabrication of impression tray
• Final impression,Beading,Boxing & pouring
• Record base fabrication
• Occlusion rims
• Mounting the casts onto the articulator

• Arranging & Articulating the Artificial teeth
-Anterior teeth arrangement
-posterior teeth arrangement
• Waxing & Carving the trial denture
• Processing the waxed up dentures
• Deflasking the processed dentures
• Lab remounting
• Finishing & polishing
• Duplicating dentures
• Review of Literature
• Summary & conclusion References

INTRODUCTION

POURING THE DIAGNOSTIC IMPRESSION &
MAKING THE DIAGNOSTIC CAST
• Preliminary care of the impression…
• Pouring the impression …
• Separate the cast & Trim the excess

IDEAL REQUIREMENTS OF THE CAST
• Cast surface should be free of voids
,nodules.
• Extend sufficiently…
• Land area…
• Base of the cast…

Purpose of making the diagnostic cast
• To measure the depth & extent of undercuts.
• Determine the path of insertion..
• Plan the preprosthetic surgeries…
• Evaluate size & contour of the arch…

Surveying the diagnostic castSurveying the diagnostic cast
• Measuring depth of undercut.
-Mounting the cast
-Tilting the cast- to change the path of insertion.
-Mark the height of contour.
-Mark the depth of undercut.
-Mock surgery is done ..

POURING THE PRIMARY CAST
• Preliminary care of the impression…
• Pour the impression…

FABRICATION OF THE SPCIAL TRAY
• Custom tray :(GPT)
An individualized tray made on a cast recovered from
the preliminary impression. Used for making final
impression.
• A custom made device prepared for a particular patient
which is used to carry, confine & control an impression
material while making an impression.

IDEAL REQUIREMENTS OF THE SPECIAL
TRAY
• Rigid
• Dimensionally stable..
• Should not react with impression material.
• Simple method of fabrication
• 2mm in thickness & 2 mm short of the
sulcus depth.

MATERIAL USED
• Shellac
• Auto polymerizing acrylic resin
• Heat cured acrylic resin
• Vacuum formed thermoplastic resin
• Type II impression compound

FABRICATION OF AUTOPOLYMERIZING
RESIN SPECIAL TRAY
• PROCEDURE:
• Mark the outline of relief,spacer.
• Adapt relief wax.
• Block out..
• Adapt spacer..
• Apply separating media.
• Sprinkle on or dough method.
• Make handle.
• Trim…

SPRINKLE ON METHOD
•Advantages
•Dis advantages

DOUGH METHOD
•Advantages.
•Disadvantages

VACUUM ADAPTED THRMOPLATIC RESIN
• Procedure
• Spacer..
• Center the cast on the vacuum adapter plate.
• Place the resin sheet in the heating frame & rotate the
heating unit into position.
• Heating until sheet sags.
• Lower the frame & resin sheet onto the cast & start
vacuum adaptation. .
• Trim the excess remove from the cast &final trim .
• Adapt handle

SHELLAC TRAY
• Procedure
• Advantages.
• Disadvantages.

FINAL IMPRESSION BEADING, BOXING &
POURING
• WAX BOXING METHOD
-Procedure
-Advantages

BOLOURI, TERENE, MAYNARD GOWRYLOK
TECHNIQUE(1975)
• Pour the plaster base & lightly seat the
impression into the plaster leaving the
peripheral turn at least 4mm above.
• Trim the excess leaving 5mm wide & 4mm
below the impression
• Adapt modeling clay , plasticine.
• Apply separating media.
• Boxing.

 Plaster & pumice mix boxing method.
 Caulking compound & Paddle boxing Method Blank
1961.
• Beading with Caulking compound rope.
• Boxing with metal strip secure with rubber band seal to
the wax paddle.
• Pour the impression.

• A study was conducted by Jhon M Young (1975)
He made the stone casts & test specimens in two methods.
One group fluid dental stone cast was allowed to set
vertically against the impression,other group allowed to set
against impression inverted.Rough grainy appearing cast
surfaces with samples set against inverted impression.
• He concluded that stone should be allowed to set against
impression material, So that the contaminants & liquid rise
to the surface away from the impression surface.

RECORD BASE
• Ideal requirements…Elder
• Adaptation
• Border form
• Rigidity
• Simple ,quick , inexpensive fabrication.
• Means for recording jaw relation , teeth arrangement.
• Kenneth added----Not to abrade the cast
-Take advantage of undercut
-Bond with block out material.

FABRICATION OF RECORD BASE WITH
AUTOPOLYMERIZING RESIN
• Sprinkle on method
• Dough method
• Confined dough methods.

• A technique by AssadzadeYarmond(1975)
--Block out…
--Adapt wax sheet on the cast & duplicate
--Place acrylic mix on the mold & close with the cast.
• Advantages ---
• Disadvantages---

Method given by Levere , Freda

FLUID RESIN BASEPLATES

• Heat cure acrylic base plate
• Shellac base plate.
• Stabilized shellac base plates
• Vacuum adapted

OCCLUSION RIMS
• Occlusion rim is defined as the “Occluding surfaces built
on permanent denture bases for the purpose of making
maxilomandibular relation records”.
• 4 basic factors to be considered are--
• 1) Relationship of natural teeth to alveolar bone
• 2) Relationship of occlusion rim to the alveolar
bone
• 3) Fabrication technique..
• 4) Clinical considerations

MOUNTING THE CASTS ON TO THE
ARTICULATOR
• The laboratory procedure of attaching the
maxillary & mandibular casts to an
articulator.

MOUNTING ON TO HANAU ARTICULATOR
 Procedure…
• Adjust the horizontal condylar guidance.
• Adjust the incisal pin..
• Attach the mounting plate.
• Face bow record transferred.
• Mounting guide as in twirl bow & spring bow,Anterior elevator ,
transfer jig used with kinematic face bow.
• Attach the cast support to the lower member of the articulator .
• Attach maxillary cast with the plaster.
• Mount the mandibular cast….
• Horizontal condylar inclination determined with the protrusive record.www.indiandentalacademy.com

MOUNTING ON TO THE WHIPMIX ARTICULATOR
• Adjust the intercondylar distance by removing the
condylar elements &using the spacers on the condylar
shaft.
• Adjust the horizontal condylar inclination.
• Attach mounting plates & plastic incisal guide table.
• Face bow record transferred.
• Mount the maxillary cast with dental plaster.
• Mount the mandibular cast.

MOUNTING WITH THE SPLIT
REMOUNTING PLATES

ARRANGING & ARTICULATING THE
ARTIFICIAL TEETH
• ARTIFICIAL TEETH…..
• Metal insert resin teeth -- Improved occlusal wear
resistance .
• Mechanical bonding
• Maintains vd
• Masticatory efficiency.

ANTERIOR TEETH ARRANGEMENT
• ARRANGING MAXILLARY TEETH.
• Definite anatomic guides used…
• Incisive papilla-
• The relationship of central incisor with the reflection of
tissue under the lip.
• Midsagittal suture

• Antero posterior positioning of the teeth
Anatomical landmarks…
• Labio lingual inclination
• Mesiodistal inclination
• Rotational positions from the incisal aspect
• Supero inferior position
• Irregularities

ARRANGING THE POSTERIOR TEETH
• Surveying the mandibular cast…
• ARRANGING 33 degree ANATOMIC TEETH..
• I premolar long axis perpendicular to the occlusal plane
• II premolar
• I molar mb & ml cusp touch the occlusal plane , db 0.5
mm & ml 0.75 mm raised.
• II molar

ARTICULATION OF THE MANDIBULAR
TEETH
• I MOLAR---
• In centric occlusion
• Working occlusion-
buccal cusps occlude. -
Distal facet of max. I PM occlude with mesiobuccal marginal
ridge of mand. I molar.
• II MOLAR
• In centric occlusion
• Working occlusion
MB cuspof mandibular II molar occludes with distal

• II PREMOLAR
• Centric occlusion
• I PREMOLAR
• Centric occlusion

• Arrange mandibular teeth first
• I & II Premolar—central fosse in line
with the antero posterior reference line.
• I Molar-- mesial cusp on plane established
by anterior & bicuspids. Distal cusp raised
by 0.5 mm.
• II Molar…
• Grinding of transverse ridge for mesio distal
unlocking of cusped teeth & buccolingual
inclines.

• ARRANGING MAXILLARY TEETH
• Modified by grinding.
• I PREMOLAR—
• II PREMOLAR– Lingual cusp occludes with distal
marginal ridge of II PM & mesial marginal ridge of I
molar.
• I MOLAR
• II MOLAR
• Balancing of the occlusion—
-Selective grinding for centric contact
--Selective grinding for working & balancing contacts.
--Selective grinding for protrusive balance.

NON ANTOMIC TEETH ARRANGEMENT
• In flat linear occlusion-- long axis at right
angles to occlusal plane& touch the
occlusal plane.
• Bilateral balance– arrange mandibular teeth
& occlude the maxillary teeth .

WAXING THE DENTURES
• The form of the polished surface of the dentures affects
esthetic & retentive quality.
• PROCEDURE
• Adapt softened roll of wax on the facial surface & contour.
• Carving to produce gingival bulge &root prominences.
• Palatal surface…
• Lingual surface
• Stippling…

FLASKING THE WAXED UP DENTURES
• The waxed up dentures are invested & mold is
created within the flask.
• PROCEDURE:

• WAX ELIMINTION

COMPRESSION MOLDING TECHNIQUE

FLUID RESIN COMPLETE DENTURE

• CURING-- the packed heat cure acrylic

DEFLSKING

LABORATORY REMOUNTING OF THE
DENTURES
• Serves as an accurate , convenient & time saving method
of reorienting the processed dentures on the articulator for
occlusal correction.
• Construction of the remounting casts.
• Preserving the orientation relation Index.
• The maxillary denture with the cast placed in the plaster
index & attached to the articulator.

FINISHING & POLISHING OF THE
DENTURES
• Remove the cast ..
• Shell blaster to remove the stone from the interior surface.
• Trim the Excess…
• Check for the nodules .
• Relive the frenii.
• Finishing of lingual border & palatal surface.
• Pumice the dentures with rag wheel inaccessible areas use
prophy cup.
• Polishing the teeth.

DUPLICATIING DENTURES

REVIEW OF THE LITERATUREREVIEW OF THE LITERATURE
• A study was conducted by Keith R Marcroft,
Tencate,William Hyrst(1961).
• They fabricated 106 complete dentures with
layered silicone rubber investing on the upper half
of the mold & 50 with all gypsum investment.
• They concluded that the wax dose not penetrate
the silicone rubber mold so separating media not
required. Reproduces carving contours accurately .
Requires less finishing &polishing.

• A study was conducted by A . Grant (1962)
• He concluded that --
• The first pour of the investment dose not
affect the position of the tooth.
• The second pore dose not affect relative
position of tooth & cast.
• Tooth movement can be minimized by
clamping the flask after investing.

• Duncan H. Wallace (1964)gave the technique to use the
Gold occlusal surfaces in resin teeth.
• He concluded that chewing efficiency increased & natural
feeling. It can be used in patients with decreased interarch
space.

• A study was conducted by Philip Schiffman (1964)
he studied the relation of the of the canine teeth to
incisive papilla in 507 casts .
• He concluded that the position pf the incisive papilla
remains fairly constant. In 78.3% of he casts the line
passing through the center of the incisive papilla joining
the canine cusp tips is perpendicular to long axis of the
cast. In 92% of the casts line passed 1mm anterior or
posterior to it.

 A technique of restoring the resin teeth with silver
amalgum restoration was given by John B.
Sowter,Robert E .Basd(1968).
• They Concluded that the efficiency of resin posterior
teeth increased & also prevent wear of the teeth.

Method of reducing the shifting of the teeth
during processing was given by Robert G.
Vig (1975).
• He showed that extension of waxed up
denture onto the posterior aspect of the cast
decreased the shifting of the posterior teeth
during processing.

.
• A study was conducted by John J. Sharry in
(1977)
• He processed the denture bases by 3
techniques & concluded that all techniques
showed dimensional changes .

• A study was conducted by Gregory Polyzois et.al
(1985).
• He processed the waxed denture bases with 3
curing cycles.
• He concluded that curing for 1.5 hr at 60degree c.
, 2.5hr at 75 de.c,100 degree c. for 1hr produces
higher degree of curing of acrylic resin

• A study wa conducted by Dr Jayavikram
under the able guidance of Sir (2001). It
was concluded that tooth movement
observed during flasking & packing . The
thickness of the flash less with Lucitone as
compared to conventional heat cure acrylic.

CONCLUSION

References
• Boucher’s Prosthodontic Treatment for edentulous patients 9th
edition.
• Charles M.Heart well’s syllabus of complete denture prosthodontics.
• DCNA Complete Dentures Robert Engelmeier 40.;1:Jan 1996
• Surface characteristic of dental stone with impression orientation John
M Young J:P:D;19975:3:33:336
• Murrow,Rudd,Rhods.Dental laboratory procedure complete denture.
• Sheldon Winkler’s Essentials of complete denture Prosthodontics 2nd
edition.
• Skinner’s Science of Dental Materials
• Zarb-Bolender’s Prosthodontic Treatment for edentulous patients 12th
edition .
• The use of gold occlusal surface in complete & partial dentures by
Duncan wallace J.P.P:1964:326:333.
• Effect of C yring cycles & denture base shape on the degree of cure of
Acrylic resin denture base Gregory Polyzois etc..all 1985:9:11.
Quintessence of Dental Technology.

• Comparision of Denture base processing technique part
II.Dimensional changes due to processing ,by
John.J.Sharry.J.P.D:1977:37:4:456.
• Fluid denture resin processing in a rigid mold by
Frank.f.Koblitz.etc al J.P.D:1973:30:339 .
• Use of layered silicone Rubber mold technique for denture
processing by Keith.R.Marcoft et al.J;P;D1961;30;657:659
• The relation of marillary canines to the ineisive papilla Philiff
Schiffman J;P;D:1964:14:469.
• Method of reducing the shifting of teeth in denture processing by
Robert.G.Vig J.P.D:1975:33:34.
• Study conducted by Philip Schiffmann in J.P.D:1964:14:469.

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Lab procedures in complete denture prosthodontics/ dental education in india

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