Wax patterns/ dentistry course in india

WAX PATTERNSWAX PATTERNS
INDIAN DENTAL ACADEMY
Leader in continuing dental education
www.indiandentalacademy.com
www.indiandentalacademy.comwww.indiandentalacademy.com

INTRODUCTIONINTRODUCTION
 The wax pattern is a precursor of the finishedThe wax pattern is a precursor of the finished
cast restoration that will be placed on thecast restoration that will be placed on the
prepared toothprepared tooth
 In as much as the wax pattern will be duplicatedIn as much as the wax pattern will be duplicated
exactly through the investing and castingexactly through the investing and casting
technique, the final restoration will be no bettertechnique, the final restoration will be no better
than its wax pattern i.e., errors and oversights inthan its wax pattern i.e., errors and oversights in
the wax pattern will only be perpetuated in thethe wax pattern will only be perpetuated in the
casting.casting.

Methods of fabrication of waxMethods of fabrication of wax
patternpattern
 Direct method : in which, the pattern is waxed onDirect method : in which, the pattern is waxed on
the prepared tooth, in the mouththe prepared tooth, in the mouth
 Indirect method: in which, the pattern is waxedIndirect method: in which, the pattern is waxed
on a stone cast made from an accurateon a stone cast made from an accurate
impression of the prepared toothimpression of the prepared tooth
 Advantages of indirect technique – affords anAdvantages of indirect technique – affords an
opportunity for visualization of restoration andopportunity for visualization of restoration and
ready access to waxing the marginsready access to waxing the margins

WAXES USEDWAXES USED
 Direct technique – type I wax is usedDirect technique – type I wax is used
 Indirect technique – type II wax is used –Indirect technique – type II wax is used –
slightly lower melting temperature thanslightly lower melting temperature than
type Itype I
 The wax used should meet ADAThe wax used should meet ADA
specification no 4specification no 4

IDEAL REQUIREMENTSIDEAL REQUIREMENTS
 It must flow readily when heated, withoutIt must flow readily when heated, without
chipping, flaking, or losing its smoothnesschipping, flaking, or losing its smoothness
 When cooled, must be rigidWhen cooled, must be rigid
 It must be capable of being carved preciselyIt must be capable of being carved precisely
without chipping, distorting or smearingwithout chipping, distorting or smearing
 The wax should of some color, such as blue,The wax should of some color, such as blue,
green, or red that will contrast with and be easilygreen, or red that will contrast with and be easily
distinguishable from the stone diedistinguishable from the stone die

WAX PATTERN FABRICATIONWAX PATTERN FABRICATION
 ARMAMENTARIUM:ARMAMENTARIUM:
 PKT [Thomas] waxing instruments [no.1, no.2, no. 3, no 4, and no.5]PKT [Thomas] waxing instruments [no.1, no.2, no. 3, no 4, and no.5]
 Beavertail burnisherBeavertail burnisher
 No 7 wax spatulaNo 7 wax spatula
 Sable brushSable brush
 No.2 pencilNo.2 pencil
 Laboratory knife with no.25 bladeLaboratory knife with no.25 blade
 Cotton pliersCotton pliers
 Bunsen burnerBunsen burner
 Inlay casting waxInlay casting wax
 Zinc stearate powderZinc stearate powder
 Die lubricantDie lubricant

Wax is added by heating the instrument in theWax is added by heating the instrument in the
bunsen flame, touching it to the wax, andbunsen flame, touching it to the wax, and
quickly reheating it shank in the flame.quickly reheating it shank in the flame.
Wax flows away from the hottest part of theWax flows away from the hottest part of the
instrument, so if the shank is heated, a bead ofinstrument, so if the shank is heated, a bead of
wax will flow off the tip.wax will flow off the tip.
However, if the tip is heated, the wax will flow upHowever, if the tip is heated, the wax will flow up
the shank of the instrument.the shank of the instrument.

The following sequence is recommended for waxThe following sequence is recommended for wax
pattern fabrication:pattern fabrication:
 Internal surface.Internal surface.
 Wax pattern removal and evaluation.Wax pattern removal and evaluation.
 Proximal surfaces.Proximal surfaces.
 Axial surfaces.Axial surfaces.
 Incisal/occlusal surface.Incisal/occlusal surface.
 Margin finishing.Margin finishing.

 Internal surface: the wax must reproduce all theInternal surface: the wax must reproduce all the
retentive features of the restoration.retentive features of the restoration.

 Wax pattern removal : Wax pattern should beWax pattern removal : Wax pattern should be
allowed to cool thoroughly before the coping isallowed to cool thoroughly before the coping is
removed from the die.removed from the die.

 Wax pattern evaluation: The objective of theWax pattern evaluation: The objective of the
first waxing step is a perfectly adaptedfirst waxing step is a perfectly adapted
reproduction of the prepared tooth surfaces.reproduction of the prepared tooth surfaces.

Coping fabricationCoping fabrication
 First step – fabrication of a thin coping /First step – fabrication of a thin coping /
thimble, on the diethimble, on the die
 It is made of wax, but heated resin sheetsIt is made of wax, but heated resin sheets
can also be usedcan also be used
 Vaccum adapted polystrene and pressureVaccum adapted polystrene and pressure
formed polypropylene have been used forformed polypropylene have been used for
making metal ceramic crown patternsmaking metal ceramic crown patterns

 It serves as a foundation for the axialIt serves as a foundation for the axial
contours and occlusal morphologycontours and occlusal morphology
 To prevent the wax from sticking to theTo prevent the wax from sticking to the
stone die, it is coated with a die lubricantstone die, it is coated with a die lubricant
and allowed to soak for several minutes.and allowed to soak for several minutes.
Repeat application if the die appears dry.Repeat application if the die appears dry.
Remove any excess lubricant with aRemove any excess lubricant with a
gentle stream of compressed airgentle stream of compressed air

 Flow wax over the surface of theFlow wax over the surface of the
preparation on the die , using quickpreparation on the die , using quick
strokes of a hot no 7 wax spatula. Overlapstrokes of a hot no 7 wax spatula. Overlap
and remelt the margins of wax alreadyand remelt the margins of wax already
placed on the die – to prevent flow lines orplaced on the die – to prevent flow lines or
voids.voids.
 Dipping the die into a small metalDipping the die into a small metal
container filled with molten wax is anothercontainer filled with molten wax is another
method that can be used for developing amethod that can be used for developing a
uniform, thin initial coping of wax on theuniform, thin initial coping of wax on the
diedie

 To ensure that the finished restoration willTo ensure that the finished restoration will
have adequate proximal contact with thehave adequate proximal contact with the
adjacent teeth, the wax pattern should beadjacent teeth, the wax pattern should be
slightly oversized mesiodistally – toslightly oversized mesiodistally – to
provide enough bulk in the contact areasprovide enough bulk in the contact areas
to allow casting, finishing, and polishingto allow casting, finishing, and polishing
without creating an open contact in thewithout creating an open contact in the
finished restorationfinished restoration
 The best way for achieving this is toThe best way for achieving this is to
remove a smal amount of stone from theremove a smal amount of stone from the
proximal surfaces of the cast on eitherproximal surfaces of the cast on either
side of the prepared toothside of the prepared tooth

Axial contoursAxial contours
 The proximal contacts of posterior teeth areThe proximal contacts of posterior teeth are
located in the occlusal third of the crowns exceptlocated in the occlusal third of the crowns except
between the maxillary first and second molars,between the maxillary first and second molars,
which is located in the middle thirdwhich is located in the middle third
 The contact must be more than just a pointThe contact must be more than just a point
occlusogingivally, but it must not extend farocclusogingivally, but it must not extend far
enough cervically to encroach on the gingivalenough cervically to encroach on the gingival
embrasure.embrasure.
 The axial surface of the crown cervical to theThe axial surface of the crown cervical to the
contact point should be flat or slightly concavecontact point should be flat or slightly concave

 A flat contour may be the optimal shape as it isA flat contour may be the optimal shape as it is
the easiest to floss.the easiest to floss.
 Proximal contacts are located slightly to theProximal contacts are located slightly to the
facial aspect of the middle of the posterior teeth,facial aspect of the middle of the posterior teeth,
except between the maxillary first and secondexcept between the maxillary first and second
molars, which is located in the centermolars, which is located in the center
faciolinguallyfaciolingually
 Contacts that are too narrow allow fibrous foodsContacts that are too narrow allow fibrous foods
to wedge between the teeth, while contacts thatto wedge between the teeth, while contacts that
are wide facioligually do not adequately deflectare wide facioligually do not adequately deflect
food from the gingival tissuefood from the gingival tissue

 The facial and lingual contours should be inThe facial and lingual contours should be in
harmony with those of the adjacent teethharmony with those of the adjacent teeth
 Height of contour on the facial surface of allHeight of contour on the facial surface of all
posterior teeth extends horizontally 0.5mmposterior teeth extends horizontally 0.5mm
beyond the plane of the tooth.beyond the plane of the tooth.
 On the lingual surface of the maxillary teeth andOn the lingual surface of the maxillary teeth and
mandibular first premolars, the height of contourmandibular first premolars, the height of contour
extends about 0.5mm, but it increases to 0.75extends about 0.5mm, but it increases to 0.75
mm on the mandibular second premolar andmm on the mandibular second premolar and
nearly 1mm on mandibular molarsnearly 1mm on mandibular molars

 Incisal/occlusal surface: Opposing incisorsIncisal/occlusal surface: Opposing incisors
should make even contact during protrusiveshould make even contact during protrusive
movements but not during lateral excursions.movements but not during lateral excursions.
The cusps and ridges of the occlusal surfacesThe cusps and ridges of the occlusal surfaces
should be shaped as to allow even contact withshould be shaped as to allow even contact with
the opposing teeth while stabilizing the teeththe opposing teeth while stabilizing the teeth
and directing the forces along the long axes ofand directing the forces along the long axes of
the teeth.the teeth.

 Margin finishing: For finalizing and adaptation,Margin finishing: For finalizing and adaptation,
the margins should be reflowed and refinishedthe margins should be reflowed and refinished
immediately prior to investing the wax pattern.immediately prior to investing the wax pattern.

EMERGENCE PROFILEEMERGENCE PROFILE
 STEIN and KUWATA described emergenceSTEIN and KUWATA described emergence
profile as the part of the axial contour thatprofile as the part of the axial contour that
extends from the base of the gingival sulcusextends from the base of the gingival sulcus
past the free margin of the gingivapast the free margin of the gingiva
 the emergence profile extends to the height ofthe emergence profile extends to the height of
contour, producing a straight profile in thecontour, producing a straight profile in the
gingival third of the axial surfacegingival third of the axial surface
 Production of a straight profile should be theProduction of a straight profile should be the
treatment objective in restoring a tooth, as ittreatment objective in restoring a tooth, as it
facilitates access for oral hygiene measuresfacilitates access for oral hygiene measures

 The most common error relating to axialThe most common error relating to axial
contour is the creation of a bulge orcontour is the creation of a bulge or
excessive concavityexcessive concavity
 Overcontoured restorations with largeOvercontoured restorations with large
convexities promote the accumulation ofconvexities promote the accumulation of
food debris and plaque, and gingivalfood debris and plaque, and gingival
inflammation results.inflammation results.

OCCLUSAL MORPHOLOGYOCCLUSAL MORPHOLOGY
 Waxing of the occlusal surface is deferred untilWaxing of the occlusal surface is deferred until
the axial surfaces are essentially completethe axial surfaces are essentially complete
 Functional cusps – palatal cusps of the maxillaryFunctional cusps – palatal cusps of the maxillary
posterior teeth and buccal cusps of theposterior teeth and buccal cusps of the
mandibular posterior teeth – help in grinding ofmandibular posterior teeth – help in grinding of
foodfood
 Non – functional cusps – buccal cusps of theNon – functional cusps – buccal cusps of the
maxillary molars and the lingual cusps of themaxillary molars and the lingual cusps of the
mandibular molars – act as a rim of a pestle tomandibular molars – act as a rim of a pestle to
prevent food from overflowingprevent food from overflowing

Classification of occlusal arrangementsClassification of occlusal arrangements
Cusp -fossaCusp -fossa Cusp –marginal ridgeCusp –marginal ridge
Location of occlusalLocation of occlusal
contact on opposingcontact on opposing
toothtooth
Occlusal fossaOcclusal fossa Occlusal fossae andOcclusal fossae and
marginal ridgesmarginal ridges
Relation with opposingRelation with opposing
teethteeth
Tooth –to - toothTooth –to - tooth Tooth-to-two-teethTooth-to-two-teeth
advantagesadvantages Occlusal forces directedOcclusal forces directed
parallel to long axis ofparallel to long axis of
tooth- very little lateraltooth- very little lateral
stressstress
Most natural type ofMost natural type of
occlusion -95% of adults.occlusion -95% of adults.
Can be used for singleCan be used for single
restorationsrestorations
disadvantagesdisadvantages Rarely found in naturalRarely found in natural
teeth – used only whenteeth – used only when
restoring severalrestoring several
contacting teethcontacting teeth
Food impaction andFood impaction and
displacement of teethdisplacement of teeth
may arise if themay arise if the
functional cusps wedgefunctional cusps wedge
into the lingualinto the lingual
embrasureembrasure
applicationsapplications Full mouth reconstructionFull mouth reconstruction Most cast restorationsMost cast restorationswww.indiandentalacademy.comwww.indiandentalacademy.com

Mandibular cusp placementMandibular cusp placement
Mandibular buccal cuspsMandibular buccal cusps Maxillary occlusal surfacesMaxillary occlusal surfaces
Cusp-marginal ridgeCusp-marginal ridge Cusp-fossaCusp-fossa
First premolarFirst premolar M marginal ridge of 1M marginal ridge of 1stst
PMPM M fossa of the 1M fossa of the 1stst
PMPM
Second premoarSecond premoar D marginal ridge of 1D marginal ridge of 1stst
PMPM
and M marginal ridge of 2and M marginal ridge of 2ndnd
PMPM
M fossa of the 2M fossa of the 2ndnd
PMPM
MB cusp of first molarMB cusp of first molar D marginal ridge of 2D marginal ridge of 2ndnd
PMPM
and M marginal ridge of 1stand M marginal ridge of 1st
MM
M fossa of the 1M fossa of the 1stst
MM

DB cusp of first molarDB cusp of first molar C fossa of the 1C fossa of the 1stst
molarmolar C fossa of the 1C fossa of the 1stst
MM
D cusp of first molarD cusp of first molar Usually not functionalUsually not functional D fossa of the 1D fossa of the 1stst
MM
MB cusp of 2MB cusp of 2ndnd
molarmolar D marginal ridge of 1D marginal ridge of 1stst
M M fossa of the 2M M fossa of the 2NDND
MM
& M marginal ridge of 2& M marginal ridge of 2ndnd
MM
DB cusp of 2DB cusp of 2ndnd
molarmolar C fossa of the 2C fossa of the 2ndnd
molarmolar C fossa of the 2C fossa of the 2ndnd
MM
D cusp of 2D cusp of 2ndnd
molarmolar Usually not presentUsually not present Usually non-functionalUsually non-functional

MAXILLARY CUSPMAXILLARY CUSP
PLACEMENTPLACEMENTMaxillary lingual cuspsMaxillary lingual cusps Mandibular occlusalMandibular occlusal
surfacessurfaces
Cusp-marginal ridgeCusp-marginal ridge Cusp-fossaCusp-fossa
First PMFirst PM D fossa of 1D fossa of 1stst
PMPM D fossa of 1D fossa of 1stst
PMPM
SECOND PMSECOND PM D fossa of 2D fossa of 2ndnd
PMPM D fossa of 2D fossa of 2ndnd
PMPM
ML cusp of 1ML cusp of 1stst
MM C fossa of 1C fossa of 1stst
MM C fossa of 1C fossa of 1stst
MM
DL cusp of 1DL cusp of 1stst
MM D marginal ridge of 1D marginal ridge of 1stst
M & M marginal ridgeM & M marginal ridge
og 2og 2ndnd
MM
D fossa of 1D fossa of 1stst
MM
ML cusp of 2ML cusp of 2ndnd
MM C fossa of 2C fossa of 2NDND
MM C fossa of 2C fossa of 2ndnd
MM
DL cusp of 2DL cusp of 2ndnd
MM D marginal ridge ofD marginal ridge of
ndnd
D fossa of 2D fossa of 2ndnd
MMwww.indiandentalacademy.comwww.indiandentalacademy.com

CUSP-MARGINAL RIDGECUSP-MARGINAL RIDGE
ARRANGEMENTARRANGEMENT
 This technique was originally devised byThis technique was originally devised by
EV Payne. It was the first wax-addedEV Payne. It was the first wax-added
technique for functional waxingtechnique for functional waxing

CUSP-MARGINAL RIDGE FORCUSP-MARGINAL RIDGE FOR
MAXILLARY TEETHMAXILLARY TEETH

Gnathologic Concept:Gnathologic Concept:
TripodismTripodism
 A cusp fossa relation in which the centricA cusp fossa relation in which the centric
cusp makes contact with the occlusalcusp makes contact with the occlusal
fossa of the opposing tooth at three pointsfossa of the opposing tooth at three points
of each cusp in each opposing fossaof each cusp in each opposing fossa
 The three contact points are the threeThe three contact points are the three
ridges which for the fossa against theridges which for the fossa against the
opposing centric cusp.opposing centric cusp.
 Achieved because of the rounded natureAchieved because of the rounded nature
of the cusp ridgesof the cusp ridges

 Tripod contacts are immediately separatedTripod contacts are immediately separated
when the mandible performs lateralwhen the mandible performs lateral
excursions and protrusive excursionsexcursions and protrusive excursions
 The centric contacts are immediatelyThe centric contacts are immediately
discluded into groove or into interproximaldiscluded into groove or into interproximal
embrasuresembrasures

 Advantages of Tripodism:Advantages of Tripodism:
– Minimum wear of the cusps tips and cusp shapes isMinimum wear of the cusps tips and cusp shapes is
maintainedmaintained → prevents the tip of a cusp to come into→ prevents the tip of a cusp to come into
contact with the fossa of the opposing toothcontact with the fossa of the opposing tooth
– Gives Stability to Centric OcclusionGives Stability to Centric Occlusion → forces are→ forces are
directed near the centre of the toothdirected near the centre of the tooth
– Distributes Forces on an Individual ToothDistributes Forces on an Individual Tooth → Allows a→ Allows a
multiplicity of pin point contactsmultiplicity of pin point contacts
– Soft Tissue ProtectionSoft Tissue Protection → minimum lateral force placed→ minimum lateral force placed
on the tooth is better tolerated by the periodontalon the tooth is better tolerated by the periodontal
membranemembrane
– Keeps the Interproximal Contacts IntactKeeps the Interproximal Contacts Intact

Additive TechniqueAdditive Technique

Additive techniqueAdditive technique
 Provides an organized step-by-stepProvides an organized step-by-step
procedure to develop the occlusalprocedure to develop the occlusal
anatomic formanatomic form
 Better understanding of the effects ofBetter understanding of the effects of
articulation on the individual elements ofarticulation on the individual elements of
the occlusal form than the carvingthe occlusal form than the carving
techniquetechnique

Step 1: Buildup of ConesStep 1: Buildup of Cones
 Centric Cusp tips are developedCentric Cusp tips are developed
 Centric cones placed at the appropriateCentric cones placed at the appropriate
mesiodistal position on the BO or LO lines.mesiodistal position on the BO or LO lines.
 Diameter of the base of the cone is oneDiameter of the base of the cone is one
third of the mesiodistal diameter of thethird of the mesiodistal diameter of the
respective cusprespective cusp

For a Maxillary 1For a Maxillary 1stst
Molar…Molar…
 Give sufficient space to wax the centric cuspGive sufficient space to wax the centric cusp
ridge and triangular ridgesridge and triangular ridges
 Wax the mesiolingual cusp to contact a flat areaWax the mesiolingual cusp to contact a flat area
located in the central fossa of the mandibular 1located in the central fossa of the mandibular 1stst
molarmolar
 Then wax the distolingual cusp to contact theThen wax the distolingual cusp to contact the
marginal ridge of the mandibular 1marginal ridge of the mandibular 1stst
molarmolar
DEVELOP THE CONTACTS ONLY ON THEDEVELOP THE CONTACTS ONLY ON THE
CUSP TIPSCUSP TIPS

Step 2: Mesial and Distal MarginalStep 2: Mesial and Distal Marginal
RidgesRidges
 Develop the mesial and distal marginal ridges inDevelop the mesial and distal marginal ridges in
a triangular shape with the apex on the trianglea triangular shape with the apex on the triangle
at the occlusal pitat the occlusal pit
 Mesial marginal ridge should contact theMesial marginal ridge should contact the
opposing cusp on the central fossa lineopposing cusp on the central fossa line
 Distal marginal ridge should be formed to theDistal marginal ridge should be formed to the
same height as the adjacent marginal ridges.same height as the adjacent marginal ridges.
 From occlusal view: marginal ridges shouldFrom occlusal view: marginal ridges should
converge to the lingual, creating a greaterconverge to the lingual, creating a greater
lingual than buccal embrasure.lingual than buccal embrasure.

Step 3: Central Fossa Contact AreaStep 3: Central Fossa Contact Area
 Contact area should have a superiorContact area should have a superior
surface that is slightly convex with thesurface that is slightly convex with the
highest point at the center.highest point at the center.
 From occlusal view: area is rhomboidalFrom occlusal view: area is rhomboidal
shaped with each apex fitting into ashaped with each apex fitting into a
development occlusal groovedevelopment occlusal groove
 Mesiodistal and buccal diameters shouldMesiodistal and buccal diameters should
be approx 2mmbe approx 2mm

Step 4: Lingual Cusp RidgesStep 4: Lingual Cusp Ridges
 Should have a definite convexity between theShould have a definite convexity between the
lingual height of contour and the cusp tiplingual height of contour and the cusp tip
 From lingual View: Should be triangular withFrom lingual View: Should be triangular with
apex at the cusp tip and base at the wax copingapex at the cusp tip and base at the wax coping
 SHOULD NOT MODIFY THE EXISTINGSHOULD NOT MODIFY THE EXISTING
CUSP TIPS – THEY DO NOT CONTACTCUSP TIPS – THEY DO NOT CONTACT
THE OPPOSING TEETH IN CENTRICTHE OPPOSING TEETH IN CENTRIC
AND ECCENTRIC POSITIONSAND ECCENTRIC POSITIONS

Step 5: Mesial and Distal LingualStep 5: Mesial and Distal Lingual
Cusp RidgesCusp Ridges
 Should not alter the cusp tipShould not alter the cusp tip
 Should provide physiologic occlusalShould provide physiologic occlusal
embrasures and proper transitional lineembrasures and proper transitional line
angles.angles.
 Most not contact the opposing toothMost not contact the opposing tooth
 Should leave sufficient space for theShould leave sufficient space for the
triangular and oblique ridges.triangular and oblique ridges.

Step 6: Functional Cusp TriangularStep 6: Functional Cusp Triangular
RidgesRidges
 Extends from the cusp tip to the centralExtends from the cusp tip to the central
fossafossa
 Should be convex from the cusp tip to theShould be convex from the cusp tip to the
central fossa and from the mesial to thecentral fossa and from the mesial to the
distal aspect.distal aspect.
 Should have a greater mesiodistal width atShould have a greater mesiodistal width at
the central fossa than at the cusp tip andthe central fossa than at the cusp tip and
should slope down from the cusp tip to theshould slope down from the cusp tip to the
fossa.fossa.

 Supplemental grooves should beSupplemental grooves should be
developed to separate the mesial anddeveloped to separate the mesial and
distal aspects of the lingual cusp ridgesdistal aspects of the lingual cusp ridges
from the respective ML and DL triangularfrom the respective ML and DL triangular
ridges.ridges.

Step 7: Non-Centric Cusp tipsStep 7: Non-Centric Cusp tips
 Should be developed on the corresponding BOShould be developed on the corresponding BO
lineline
 Should vertically and horizontally overlap theShould vertically and horizontally overlap the
opposing tooth in the occluded position.opposing tooth in the occluded position.
 In laterotrusion these cusps are developed toIn laterotrusion these cusps are developed to
pass through the embrasures and grooves of thepass through the embrasures and grooves of the
opposing teeth without contact.opposing teeth without contact.
 Sufficient room should be provided to allow waxSufficient room should be provided to allow wax
up of the surrounding cuspal ridges.up of the surrounding cuspal ridges.

Step 8: Buccal Cusp RidgesStep 8: Buccal Cusp Ridges
 Should blend into the buccal cusp conesShould blend into the buccal cusp cones
 Should be triangular with apex at the cuspShould be triangular with apex at the cusp
tip and base on the wax copingtip and base on the wax coping
 Should not modify the existing cusp tipShould not modify the existing cusp tip
 No contact with the opposing tooth inNo contact with the opposing tooth in
centric and eccentric positionscentric and eccentric positions

Step 9: Mesiobuccal andStep 9: Mesiobuccal and
Distobuccal cusp ridgesDistobuccal cusp ridges
 Each has a slight convexity between the buccal crest ofEach has a slight convexity between the buccal crest of
contour and the BO line.contour and the BO line.
 Do not modify the existing cusp tip or contact anyDo not modify the existing cusp tip or contact any
opposing tooth surface in any centric or eccentricopposing tooth surface in any centric or eccentric
positionposition
 Transition should be continuous with the remaining waxTransition should be continuous with the remaining wax
pattern providing physiologic embrasurespattern providing physiologic embrasures
 Inner aspects are convex surfaces that slope down intoInner aspects are convex surfaces that slope down into
the marginal ridges and form the buccal portion of thethe marginal ridges and form the buccal portion of the
MB and DO FossaMB and DO Fossa
 Mesiobuccoocclusal and distobuccoocclusal point anglesMesiobuccoocclusal and distobuccoocclusal point angles
should align buccolingually with the point angle of theshould align buccolingually with the point angle of the
adjacent teeth providing physiologic occlusal embrasure.adjacent teeth providing physiologic occlusal embrasure.

Step 10: Buccal Cusp TriangularStep 10: Buccal Cusp Triangular
RidgesRidges
 Should be convex in all dimensions.Should be convex in all dimensions.
 Greater MD width at the central fossa line thanGreater MD width at the central fossa line than
the cusp tip line.the cusp tip line.
 Supplemental grooves are developed toSupplemental grooves are developed to
separate the mesial and distal aspects of theseparate the mesial and distal aspects of the
buccal cusp triangular ridges from the respectivebuccal cusp triangular ridges from the respective
inner aspects of the MB and DB cusp ridges.inner aspects of the MB and DB cusp ridges.
 Do not contact the opposing teeth in any centricDo not contact the opposing teeth in any centric
or eccentric position.or eccentric position.

Subtractive TechniqueSubtractive Technique

 Develop Axial Contours on the dies.Develop Axial Contours on the dies.
 Block out areas of the functional core thatBlock out areas of the functional core that
should not contact the wax.should not contact the wax.
 Lubricate the blocked out coreLubricate the blocked out core
 Warm the tip of a chip blowerWarm the tip of a chip blower
 Heat each occlusal surface separately withHeat each occlusal surface separately with
warm air stream from the chip blowerwarm air stream from the chip blower
 Close the lubricated functional core onto the softClose the lubricated functional core onto the soft
occlusal wax and observe the wax patternocclusal wax and observe the wax pattern

 Repeat the above procedure for each waxRepeat the above procedure for each wax
pattern.pattern.
 Close the functional core into all the waxClose the functional core into all the wax
patterns at the same time, making surepatterns at the same time, making sure
the guide pin touches the tablethe guide pin touches the table
 Coat the occlusal of the anatomic castCoat the occlusal of the anatomic cast
 Close the anatomic cast into the waxClose the anatomic cast into the wax
pattern making the contacts in white onpattern making the contacts in white on
the wax patternsthe wax patterns
 Carve anatomic contours into the occlusalCarve anatomic contours into the occlusal
surface, taking care to avoid carving awaysurface, taking care to avoid carving away
the white occlusal contactsthe white occlusal contacts

 Round the carved occlusal of the wax pattern ofRound the carved occlusal of the wax pattern of
the wax pattern with a gentle warm air streamthe wax pattern with a gentle warm air stream
from a heated chip blowerfrom a heated chip blower
 Close the functional into the warmed occlusal ofClose the functional into the warmed occlusal of
the wax pattern.the wax pattern.
 Remove any excess wax and round anyRemove any excess wax and round any
flattened areas with a carving instrumentflattened areas with a carving instrument
 Smooth the occlusal of the wax pattern with aSmooth the occlusal of the wax pattern with a
gentle, warm air stream from a heated chipgentle, warm air stream from a heated chip
blower and check the finished wax pattern bothblower and check the finished wax pattern both
the functional core and the anatomic cast.the functional core and the anatomic cast.

MARGIN FINISHINGMARGIN FINISHING
 The margin is critically important area of any waxThe margin is critically important area of any wax
pattern. While a good margin may not insure the successpattern. While a good margin may not insure the success
of a casting, a poor one can almost guarantee its failureof a casting, a poor one can almost guarantee its failure
 Smooth any roughness on the axial surface with aSmooth any roughness on the axial surface with a
slightly warm beavertail burnisher.slightly warm beavertail burnisher.
 Any excess wax is carved almost to the margin with aAny excess wax is carved almost to the margin with a
PKT no4.PKT no4.
 Finish carving the margin with a slightly warm beavertailFinish carving the margin with a slightly warm beavertail
burnisherburnisher
 Do not approach the finish line on the die with a sharpDo not approach the finish line on the die with a sharp
instrument as it can remove die material as well as theinstrument as it can remove die material as well as the
wax margins, resulting in a casting that will not fit thewax margins, resulting in a casting that will not fit the
prepared toothprepared tooth

 OVERWAXED MARGINS: areas in which waxOVERWAXED MARGINS: areas in which wax
has been carried past the finish line may breakhas been carried past the finish line may break
off when the pattern is withdrawn from the die,off when the pattern is withdrawn from the die,
resulting in a short or shy margin. If theresulting in a short or shy margin. If the
overwaxes area does not break off, it may springoverwaxes area does not break off, it may spring
back. When cast in metal, this area will noback. When cast in metal, this area will no
longer bend as it once did in wax, and thelonger bend as it once did in wax, and the
casting may be prevented from seating all thecasting may be prevented from seating all the
way on the toothway on the tooth
 SHORT MARGINS: will not provide an adequateSHORT MARGINS: will not provide an adequate
seal for the finished restorationsseal for the finished restorations

 RIPPLES: any roughness in wax near theRIPPLES: any roughness in wax near the
margin will be duplicated in the casting. Ifmargin will be duplicated in the casting. If
allowed to remain on the finished, cementedallowed to remain on the finished, cemented
restorations, these areas act as colecting pointrestorations, these areas act as colecting point
for plaque, leading to irritation and inflammationfor plaque, leading to irritation and inflammation
of the gingival tissue.of the gingival tissue.
 THICK MARGINS: a thick, rounded margin willTHICK MARGINS: a thick, rounded margin will
result in poor sealing of the restoration and poorresult in poor sealing of the restoration and poor
axial contours that will ultimately lead toaxial contours that will ultimately lead to
periodontal problems. The margins must comeperiodontal problems. The margins must come
to a knife edgeto a knife edge
 OPEN MARGINS: attention to detail is essentialOPEN MARGINS: attention to detail is essential
to produce close margins. The pattern must beto produce close margins. The pattern must be
burnished and melted, as well as cut, to ensureburnished and melted, as well as cut, to ensure
close adaptation of the wax to the die in theclose adaptation of the wax to the die in the
marginal areasmarginal areas

 To finish the occlusal grooves, hold a veryTo finish the occlusal grooves, hold a very
small cotton pellet in cotton pliers and dipsmall cotton pellet in cotton pliers and dip
it in the die lubricant. Run the pelletit in the die lubricant. Run the pellet
carefully through the groovescarefully through the grooves
 Same method is employed to finish theSame method is employed to finish the
axial surfaces.axial surfaces.
 Avoid excessive or prolonged buffingAvoid excessive or prolonged buffing
action near marginsaction near margins
 Remove all lubricant from pattern onceRemove all lubricant from pattern once
polishing is over. Any lubricant left on thepolishing is over. Any lubricant left on the
pattern when it is invested can causepattern when it is invested can cause
surface roughnesssurface roughness

 Depressions cannot be polished away.Depressions cannot be polished away.
They are better removed by filling themThey are better removed by filling them
with wax and then smoothening themwith wax and then smoothening them
 The purpose of finishing is to provide aThe purpose of finishing is to provide a
smooth surface for castingsmooth surface for casting
 Wax is softer than metal. Anything thatWax is softer than metal. Anything that
can be done in wax, as opposed to doingcan be done in wax, as opposed to doing
it later in metal, should be. In wax,it later in metal, should be. In wax,
anything can be done in a fraction of time,anything can be done in a fraction of time,
with less effort, and with better results.with less effort, and with better results.

Wax patterns/ dentistry course in india

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