Wax patterns/ dentistry course in india

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Wax patterns/ dentistry course in india

  1. 1. WAX PATTERNSWAX PATTERNS INDIAN DENTAL ACADEMY Leader in continuing dental education www.indiandentalacademy.com www.indiandentalacademy.comwww.indiandentalacademy.com
  2. 2. 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. www.indiandentalacademy.comwww.indiandentalacademy.com
  3. 3. 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 www.indiandentalacademy.comwww.indiandentalacademy.com
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  5. 5. 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 www.indiandentalacademy.comwww.indiandentalacademy.com
  6. 6. 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 www.indiandentalacademy.comwww.indiandentalacademy.com
  7. 7. 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 www.indiandentalacademy.comwww.indiandentalacademy.com
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  9. 9. 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. www.indiandentalacademy.comwww.indiandentalacademy.com
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  11. 11. 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. www.indiandentalacademy.comwww.indiandentalacademy.com
  12. 12.  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. www.indiandentalacademy.comwww.indiandentalacademy.com
  13. 13.  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. www.indiandentalacademy.comwww.indiandentalacademy.com
  14. 14.  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. www.indiandentalacademy.comwww.indiandentalacademy.com
  15. 15. 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 www.indiandentalacademy.comwww.indiandentalacademy.com
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  17. 17.  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 www.indiandentalacademy.comwww.indiandentalacademy.com
  18. 18.  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 www.indiandentalacademy.comwww.indiandentalacademy.com
  19. 19.  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 www.indiandentalacademy.comwww.indiandentalacademy.com
  20. 20. 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 www.indiandentalacademy.comwww.indiandentalacademy.com
  21. 21.  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 www.indiandentalacademy.comwww.indiandentalacademy.com
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  24. 24.  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 www.indiandentalacademy.comwww.indiandentalacademy.com
  25. 25.  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. www.indiandentalacademy.comwww.indiandentalacademy.com
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  28. 28.  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. www.indiandentalacademy.comwww.indiandentalacademy.com
  29. 29. 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 www.indiandentalacademy.comwww.indiandentalacademy.com
  30. 30.  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. www.indiandentalacademy.comwww.indiandentalacademy.com
  31. 31. 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 www.indiandentalacademy.comwww.indiandentalacademy.com
  32. 32. 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
  33. 33. 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 www.indiandentalacademy.comwww.indiandentalacademy.com
  34. 34. 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 www.indiandentalacademy.comwww.indiandentalacademy.com
  35. 35. 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
  36. 36. 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 www.indiandentalacademy.comwww.indiandentalacademy.com
  37. 37. CUSP-MARGINAL RIDGE FORCUSP-MARGINAL RIDGE FOR MAXILLARY TEETHMAXILLARY TEETH www.indiandentalacademy.comwww.indiandentalacademy.com
  38. 38. 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 www.indiandentalacademy.comwww.indiandentalacademy.com
  39. 39.  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 www.indiandentalacademy.comwww.indiandentalacademy.com
  40. 40.  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 www.indiandentalacademy.comwww.indiandentalacademy.com
  41. 41. Additive TechniqueAdditive Technique www.indiandentalacademy.comwww.indiandentalacademy.com
  42. 42. 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 www.indiandentalacademy.comwww.indiandentalacademy.com
  43. 43. 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 www.indiandentalacademy.comwww.indiandentalacademy.com
  44. 44. 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 www.indiandentalacademy.comwww.indiandentalacademy.com
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  46. 46. 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. www.indiandentalacademy.comwww.indiandentalacademy.com
  47. 47. 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 www.indiandentalacademy.comwww.indiandentalacademy.com
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  49. 49. 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 www.indiandentalacademy.comwww.indiandentalacademy.com
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  51. 51. 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. www.indiandentalacademy.comwww.indiandentalacademy.com
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  53. 53. 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. www.indiandentalacademy.comwww.indiandentalacademy.com
  54. 54.  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. www.indiandentalacademy.comwww.indiandentalacademy.com
  55. 55. 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. www.indiandentalacademy.comwww.indiandentalacademy.com
  56. 56. 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 www.indiandentalacademy.comwww.indiandentalacademy.com
  57. 57. 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. www.indiandentalacademy.comwww.indiandentalacademy.com
  58. 58. 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. www.indiandentalacademy.comwww.indiandentalacademy.com
  59. 59. Subtractive TechniqueSubtractive Technique www.indiandentalacademy.comwww.indiandentalacademy.com
  60. 60.  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 www.indiandentalacademy.comwww.indiandentalacademy.com
  61. 61.  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 www.indiandentalacademy.comwww.indiandentalacademy.com
  62. 62.  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. www.indiandentalacademy.comwww.indiandentalacademy.com
  63. 63. 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 www.indiandentalacademy.comwww.indiandentalacademy.com
  64. 64. www.indiandentalacademy.comwww.indiandentalacademy.com
  65. 65.  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 www.indiandentalacademy.comwww.indiandentalacademy.com
  66. 66.  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 www.indiandentalacademy.comwww.indiandentalacademy.com
  67. 67.  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 www.indiandentalacademy.comwww.indiandentalacademy.com
  68. 68.  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. www.indiandentalacademy.comwww.indiandentalacademy.com
  69. 69. www.indiandentalacademy.comwww.indiandentalacademy.com

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