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Dental Wax Material PPT.pdf
- 1. 1 Dr.Himanshu Tiwari Senior Lecturer Dept.Of Prosthodontics and Crown & Bridge Dental Wax Materials
- 2. ⚫thermoplastic molding material. ⚫solidat room temperature. 2 Definition
- 3. 🗉Baseplate wax: sheets,establish initial arch form in construction of CD. 🗉Bite wax: record the occlusal surfaces of teeth. 🗉Boxing wax: sheet wax used as a border of an impression to provide base of the cast to be made. 🗉Inlay wax: applied to dies to form direct or indirect patterns for the lost-wax tech. 🗉Sticky wax: adheres to dry clean surfaces. 3 Types of waxes
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- 6. ⚫BASE Wax: thatis almost always paraffin (not smooth, not glossy, flake when trimmed) (1) Hydrocarbon of paraffin or esters (2) High or low MW ⚫MODIFIER Waxes: contribute properties such as increased hardness, stickiness, or brittleness (1) Hydrocarbon or ester types; (2) High or low MW ⚫COLORANT: 1% ⚫Fillers: some waxes contain it to control expansion and shrinkage of the wax product. 6 General Composition
- 7. Natural (mineral, vegetable,or animal origin and/or synthetic waxes (more homogeneous & pure) Natural waxes are complex combinations of organic compounds of high molecular weight: ⚫Hydrocarbons,e.g. saturated alkanes, & microcrystalline wax series, carnauba wax, candelilla wax. ⚫Esters, e.g.myricylpalmitate. Some waxes also contain free alcohol and acid. (Esters are formed from union of higher fatty acids with higher aliphatic alcohol with elimination of water) Alcohol+Fatty Acid 🡪 Ester+Water 7 Chemical composition
- 8. Natural waxes Syntheticwaxes Additives Minerals: Paraffin Microcrystalline Barns Dahl Ozokerite Ceresin Montan Acrawax C Aerosol,OT Castorwax Flexowax C Epolene N-10 Albacer Aldo 33 Durawax 1032 Fats □Stearic acid □Glyceryltristearate □Oils □Turpentine □Color Plants :Carnauba Ouricury Candelilla Japan wax Coca butter Natural Resins □Rosin □Copal □Dammar □Sandarac □Mastin, Shellac □Kauri Insect: Beeswax Animal: Spermaceti Synthetic Resins □Elvax □Polyethylene Polystyrene 8
- 9. ⚫Gum dammar: smoothness,resistant to flaking, toughness. (resin) ⚫Ceresin the hardness and water resistance of wax. Improves carving properties. ⚫Carnuba the hardness and water resistance, melting range, gives glossiness, flow at mouth temp. ⚫Beeswax the stickiness, improves flow properties at mouth temperature. (esters) ⚫Rosin the brittleness. (resin) ⚫Microcrystalline waxes stress release on cooling. 9 Common Modifier Waxes
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- 11. ⚫Occurs because ofthe Multiple wax mixtures ⚫The liquidus line (representing the temperature at which complete melting has occurred) ⚫The solidus line (below which the composition is entirely solid) ⚫the solid + liquid range in between is quite broad (almost 40°C). To allow manipulation ⚫To develop wax flow, the temperature only needs to be heated to a point within the solid+liquid range or up to the point of the liquidus line but not much higher. ⚫Excessive heating would cause decomposition. 11 Melting range
- 12. 12 Melting range COMPOSITION (%) TEMPERATURE (C) Paraff in Carnuba 40 30 20 60 50 70 80 90 25 5075 100 LIQUID LIQUID + SOLID SOLID Melting Onset (Solidus) Melting Completion (Liquidus)
- 13. 13 Density and Meltingranges Name: Origin: Composition: Melting (°C) Density (20°C) PARAFFIN Mineral Hydrocarbon mixture 50-57 0.90 CERESIN Mineral Complex hydrocarbons 61-78 0.91-0.92 BEESWAX Animal Ester mixture 62-65 0.95-0.96 CANDELILLA Plant C21 hydrocarbons 68-70 0.95-0.99 CARNAUBA Plant Hydrocarbon, Ester, Fatty Acid 82-86 0.99-0.999 GUM DAMMAR Plant Aromatic resin ca 120 1.040- 1.120 ROSIN Plant Aromatic resin acid 100-150 1.08
- 14. Methods: 1. Flame heatedinstruments 2. warmth of hand?? 3. dry heat as wax pot 4. Water bath, but not for inlay wax?? Flow : ⚫ after the highest melting point is reached. ⚫ Temperature α 1/ viscosity ⚫ Flow temperature must be > mouth temp if needed in solid state Over heating should be avoided? the base or modifier waxes can be decomposed. 14 Heating issues
- 15. ⚫In solids itsanalogous to creep ⚫In liquids its analogous to viscosity ⚫Waxes are usually non-flowable at room temperature ⚫Temperature α 1/ viscosity ⚫It is critical for inlay wax to have flow less than 1% 15 Flow
- 16. ⚫It is low ⚫Waxshould be softened evenly by ⚫rotation above the flame until it evenly softens or flows ⚫Tempered in a water bath alternately with the flame heating to allow the core to soften before dripping ⚫If a soft core of a bulk of wax is to be made, roll the wax when it is in softened status – (unable to hold shape by itself) 16 Thermal conductivity
- 17. ⚫Used with castmetal techniques ⚫Wax patterns need to be burned to the point where no excess residue may interfere with metal casting ⚫Heat melt and/or decompose wax by the process of oxidation which completely transform it into water vapor and carbon dioxide so that no residue is left. 17 Lost wax technique
- 18. 18 Tackiness or stickiness ⚫Createdby the bees wax addition in the mixture ⚫Increased if material is warmed by hand ⚫Solid waxes become tacky to other material if heated ⚫Adhesives may be applied on casts before wax application ⚫Wax dipping in bees wax increase stickiness of refractory casts ⚫Old wax adheres to new one if surface is dry
- 19. 19 Dimensional stability ⚫Wax shouldbe dimensionally stable once it has solidified (less than 1%). ⚫ Invest the pattern immediately after removal from the die. Deformations: ⚫Plastic deformation ⚫Under force is by ductility. ⚫Ductility allows it to be carved or burnished ⚫Residual stress recovery ⚫Elastic Recovery
- 20. ⚫Residual stress reduction ⚫Heatmaterial evenly ⚫Follow manufacturer instructions ⚫Invest within 30 min of carving ⚫Whenever wax additions are cooled. The exterior surface tends to cool first. The molten interior slowly solidifies and contracts. This encourages distortion or flow. Add in small increments, layering ⚫Store at low temperatures 20 Residual stress
- 21. 21 Coefficient of thermal expansion ⚫Veryhigh ⚫ceramics (1-15 ppm/°C) ⚫metals (10-30 ppm/°C) ⚫waxes (30-600 ppm/°C) ⚫inlay wax (250-300 ppm/°C) ( wax pattern made in the mouth will shrink appreciably) ⚫Residual thermal stresses may change dimensions ⚫Paraffin > beeswax >carnuba Ñ Do not heat above melting point during work
- 22. 22 Thermal Expansion 250 ppm/° C Paraffin 0 2530 40 45 35 50 0 1.2 1.0 0.8 0.6 0.4 0.2 TEMPERATURE (C) EXPANSION (%) KERR HARD WAX
- 23. ⚫Wax is hydrophobic ⚫Toincrease its wetting a surfactant could be sprayed over wax to increase flow of investment material 23 Surface tension
- 24. ⚫Coloring is notstandardized ⚫Dark colors provide good color contrast for processing wax ⚫Opaque and Tooth-colored waxes provide good material for esthetic case presentations and patient education 24 Color
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- 28. Uses ⚫metal castings of ⚫Inlays ⚫Attachments ⚫Crowns ⚫Pontics ⚫Partialdentures ⚫ Denture base material 28 Pattern waxes
- 29. Forms sticks pallets, tins 🗉Blueor green Consistencies 🗉Hard, medium, soft, regular Application 🗉indirect and direct technique 29 Inlay wax Removable Die with Waxed Inlay
- 30. INLAY WAX Composition Paraffin +Carnuba + Ceresin +Beeswax + Colorants Properties - low thermal dimensional change - flow temp higher than mouth - must have clean excess residue 30
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- 32. Application ⮚Used for metalframework ⮚complete and partial dentures Forms Sheets and preformed shapes Properties ⮚low thermal dimensional change ⮚must have clean excess residue 32 Casting waxes
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- 35. Form sheets Types I, II& III Application 🗉wax registration of ridge form 🗉Carved into tissue forms and Support teeth 🗉Bite registration Properties 🗉melting range higher than mouth temperature 🗉Customised to climate 35 Base Plate wax
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- 37. Uses ⚫For edentulous impressions ⚫Corrects undercuts ⚫Closes bubbles Properties ⚫flow at mouth temperature ⚫E.g. Bite wax, mizzy 37 Impression wax
- 38. Wax Bite Registration Uses ⚫Toarticulate models correctly Forms ⚫horse shoe shape ⚫May be supported by metal foil for stability 38
- 39. Forms 1 inch sheets Uses usedto form base of the cast pouring May be used to modify borders of trays Properties Tacky at room temp 39 Boxing wax Transfer to impression
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- 41. Forms Ropes manipulated atroom temp Applications Add to the tray 🗉 customize for pt mouth 🗉 Comfort from sharp edges 🗉 Control imp material in mouth 🗉Cover ortho bands and wires 🗉 to register the bite 🗉Block out undercuts 41 Utility wax
- 42. Forms Pencil shape orange oryellow Properties hard and brittle – can reorient if broken Adhere temporarily the metal, gypsum, resin – for fabrication or repair 42 Sticky wax
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