Dental waxes\dental materials ppt


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Dental waxes\dental materials ppt

  2. 2. Dental waxes  variety of natural waxes and resins have been used in dentistry for specific and well defined applications.  Waxes are thermoplastic materials which are solids at room temperature but melt without decomposition to form mobile liquids.  They consist of two or more components which may be
  3. 3. THERMAL PROPERTIES OF WAXESMELTING RANGE • Waxes have a melting range rather than a melting point. • Example : paraffin 44 – 62 C⁰ carnauba 50 – 90 C⁰ • Significance: Mixing of waxes can change their melting range. COEFFICIENT OF THERMAL EXPANSION • Waxes expand when there is increase in temperature and contract when there is decrease in temp. • Dental waxes have the greatest co-efficient of thermal expansion than any other restorative materials in dentistry . • Eg : CTE of type 1 wax is[ between 22C⁰ and 37.5C ⁰] is 323 10-6 FLOW • Is the slippage of wax molecules over each other. • Measure of flow is the measure of the degree of
  4. 4. MECHANICAL PROPERTIES Compressive strength , proportional limit, elastic modulus of waxes are low. These properties strongly depends on the temperature As the temp decreases mechanical properties improveCHEMICAL NATURE  Two principle groups of organic compounds : • Hydrocarbons : saturated alkanes Esters • myricyl palmitate [bees wax]  Some waxes in addition contains free alcohol and acids
  5. 5. Dental wax component
  6. 6. PATTERN WAXES : 1. Inlay wax 2. Casting wax 3. Base plate wax 4. Wax rim 5. Shellac denture base  PROCESSING WAX: 1. Sticky wax 2. Utility wax 3. Block-out wax 4. Boxing & beading wax  IMPRESSION WAX: 1. Corrective wax 2. Bite registration Classification of dental waxes
  7. 7. Inlay wax • Classification(ADA Sp. No. 4) • It is a type of pattern wax. Type I: Medium wax employed in direct technique. Type II: Soft wax used for indirect technique for inlays and crowns. • Uses of inlay wax: 1. It is used to make patterns for metallic restorations. 2. Patterns for inlays, 3. crowns and bridges is first made in wax and then converted into metal or ceramic by casting.
  8. 8. Casting wax • It is a type of pattern wax. • Classification (According to FDI Specification No. 140). Class I : 28 gauge, pink ,Flow of about 10 % at 35C˚ Easily adaptable at 40 to 45C˚ Class II :30 gauge, green ,Minimum flow of 60 % at 38C˚ ,adapts well to the surface ,not brittle on cooling Class III: readymade shapes, blue Will burnout at 500C˚ leaving no carbon residue ,Supplied As Sheets 0.40 and 0.32 mm thickness. • Used to produce the metallic component of partial denture on the cast. Class I Class II Class III
  9. 9. Base Plate Wax • Classification (ADA Sp. No. 24) • It is a type of pattern wax. • Uses: used mainly in preparing wax patterns for prosthesis. • Supplied as : Sheets of pink or red color.
  10. 10. Wax rim (bite rim): • It is a type of pattern wax. • The softening temp. is above the mouth temp. • It is tough & resist fracture during removal from the cast. • It used for : 1. Restoring the occlusal relationship. 2. Arrangement of teeth. 3. Check the denture inside the patient mouth. Bite blockBite stick
  11. 11. Shellac denture base: • It is a type of pattern wax • Wax like resin stable at mouth temp. • It has high softening temperature than other waxes. • It is used as a temporary denture base.
  12. 12. Sticky wax: • It is a type of processing wax. • It is sticky when melted, with a max 5 %flow at 30 Cº and 90 % at 43 Cº . • It adheres closely to the surfaces when applied to it. • If movement occurs the wax tends to fracture than distort. • At room temperature the wax is brittle and breaks easily • Uses 1. It is used to align fractured parts of acrylic dentures . 2. It is used to align fixed partial denture units before soldering . 3. It is used to seal a plaster splint to the stone cast during
  13. 13. Utility Wax • It is a type of processing wax . • Supplied as : It is available in the form of sticks and sheets. Orange or dark red in color. In orthodontics, periphery wax is white in color • Flow at 37.5Cº- min. 65 % and max. 80% . • Pliable and tacky at 21-24Cº • Uses: It can be used to alter the stock tray extensions . The following alterations : 1. can be made Height of the tray .
  14. 14. Boxing & beading waxes:  It is a type of processing wax.  Use: • Beading wax is adapted around the impression borders to create the land area of the cast • Boxing wax is used to build up vertical walls around the impression in order to pour the gypsum product to make a cast base.  Supplied as : • Boxing wax as sheets. • beading wax as strips.
  15. 15. Beading upper impression
  16. 16. Boxing upper impression
  17. 17. Block out wax • It is a type of processing wax. • Used for filling the undercut area on the cast during processing of the Cr-Co frame work.
  18. 18. Block out upper cast
  19. 19. Impression waxes: Corrective wax : • Wax in combination with resins of low melting point can be used in corrective impression technique in partial and complete denture prosthesis. • The peculiarity of impression wax is that they flow at mouth temperature. • Availability : sheets or cakes • Used to restore the selected region in the edentulous patients to reproduce the details of mucous membrane. • Its main disatvantage is that it is distorted
  20. 20. Impression waxes  Bite registration wax : It is used to record the relationship of the upper & lower teeth in dentulous patients .
  21. 21. Bite registration
  22. 22. Analog Wax Heater : Dental Lab Equipment is a high quality wax pot and ideal for all dental applications. Its temperature controlled heating system gives you a broad temperature range of 70 F to 237 F (21 C to 112 C). In addition, this wax pot features an insulated thermoplastic housing which remains cool while wax stays hot!