1. Dental Waxes BY -DR KARTIK RAMAN (MDS)

2. INTRODUCTION Waxes have versatile role to play in dentistry Dental waxes may be composed of natural and synthetic resins and waxes, gums, fats, oils, fatty acids and pigments of various types. The chemical components of waxes impart characteristic physical properties to the wax.

3. COMPONENTS

4. CLASSIFICATION ACCORDING TO HISTORY Natural waxes Synthetic waxes ACCORDING TO ORIGIN Mineral Plant Insect Animal

5. CLASSIFICATION PATTERN IMPRESSION PROCESSING Inlay Boxing Corrective Casting Utility Bite Sheet Sticky Ready Shapes Wax – up

6. Pattern Waxes are used to form the general pre determined size and contour of an artificial dental restoration, which is to be contructed of a more durable material such as cast gold alloys, cobalt – chromium – nickel, acrylic resin etc.

7. Inlay Pattern Wax The lost wax technique. Inlay wax provides the wax pattern used in this technique

8. Composition – Principal waxes used are paraffin, microrystalline wax, ceresin, carnauba, candelilla and bees wax. One formulation is Paraffin – 60% - Major constituent Carnauba – 25%- – decreasing flow at mouth temp, agreeable odour imparts glossiness Ceresin - 10%- – may be added to replace part of paraffin Beeswax – 5% – improves handling characteristics

9. Types : Revised ANSI/ADA specification No. 4 (ISO 1561) - Type I – (Soft inlay wax)-utilized as an indirect technique wax. Type II – (Hard inlay wax) utilized for forming direct wax patterns in mouth where lower flow rate at 37 o C tends to minimize distortion on removal.

10. Desirable Properties Should be uniform when softened Colour contrast with die natural or prepared tooth no surface roughness or chipping, flakiness when moulded Carvability should be there. Elimination should be complete and burnout should not leave any residues on surface Dimensional stability and toughness. Should be easy to handle.

11. Flow The flow of Type II wax is no more than 1% at body temperature and that of Type I is 9%. Thermal Properties Rate of expansion of Type I wax is greatest at just above 45 o C. Wax Distortion Inlay waxes tend to return to their original shape after manipulation depicting ‘elastic memory’

12. Base Plate Wax :- used to form all or portion of tray too. Patterns for orthodontic appliances and prosthesis other than complete dentures. To check various articulating relation in mouth & transfer them to articulators.

13. Composition :- 70-80% paraffin based waxes or ceresin, 12% beeswax, 2.5% carnauba, 3% natural or synthetic resins, 2.5% Microcrystalline or synthetic Waxes

14. Types :- Type 1 :-Soft wax used for building contours and veneers Type 2:-Hard wax used for patterns to be tried in mouth in Temperate weather. Type 3:-Extra hard wax for patterns to be tried in mouth in tropical weather

15. Requirement of Base plate wax Should be easily trimmed Should yield a smooth surface after gentle flaming. Should not leave any residue on plastic or porcelain teeth & colouring agents Should not separate or impregnate the mould. Softened sheets should cohere readily without becoming flaky or adhering to fingers. No irritation to oral tissues. No adhesion to other sheets of wax or storing paper on storage

16. Bite Registration Wax Use - Used to accurately articulate certain moulds of opposing quadrants Composition :- Beeswax or hydrocarbon waxes such as paraffin or ceresin. Certain bite waxes contain aluminium or copper particles. Flow of 2.5% to 22% at 37 0 c has been suggested indicating these waxes are susceptible to distortion on removal from mouth. Special considerations to be given not to use them in undercut areas

17. Boxing Wax Used for forming a plaster or stone cast from an inpression of the edentulous arch into which freshly mixed plastic or stone is poured and vibrated. The names carding wax & boxing wax have been used interchangeably but boxing wax is more acceptable.

18. Ideal requirements It should be readily adaptable to impression. at room temp, Should be slightly tacky & have sufficient strength & roughness for convenient manipulation. Pliable at 21 0 c, retains shape at 35 0 c Smooth, glossy surface on flaming. Seals easily to plaster with hot spatula

19. DIRECT WAX TECHNIQUE Indications :- Tooth accessible in the oral cavity to work on. Cavity preparations with minimal proximal extensions Good deal of supporting tooth structure to stabilize pattern during carving Cavity preparations where walls are flat, internal line angles are sharp & gingival level is definite

20. Advantages – Direct preparation on tooth and not on a replica that may be altered. less lab work required, time saving procedure. Disadvantages – Technique sensitive & great skill required – fabrication in indirect vision difficult, – gingival discrepancies difficult to judge before withdrawal, – chairside time is increased,if casting fails patient has to be recalled.

21. Indirect wax technique Indications : When access to tooth is hampered, Chairside time has to be reduced. Extensive preparations More pressure is required.

22. Advantages :- More precise patterns. – Less chairside time – Adjustments can be done – Repeated castings can be done from single die. Disadvantages :- – Though less chairside time more lab work is requested, – The replica may be of altered dimensions.

23. Sticky wax Used to assemble metallic or resin pieces on a fixed temporary position Used primarily on dental stones & plasters for sealing purposes etc. Composition :- Rosin, yellow beeswax, Gum dammar, colouring agents

24. Requirements It should have a dark or vivid colour to be readily distinguished from light gypsum materials To be sticky when melted Adheres closely No more than 0.2 % residue or burnout No more shrinkage than 0.5 % from 43 o C to 28 0 C Max flow at 30 0 C – 5 % Min flow at 43 0 C – 90 % Should be firm, free from tackiness & brittle at room temp. Should fracture rather than flow if deformed during repair procedures.

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