Flexible dentures in rpd/ cosmetic dentistry training

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Flexible dentures in rpd/ cosmetic dentistry training

  1. 1. INDIAN DENTAL ACADEMY Leader in continuing dental education www.indiandentalacademy.com www.indiandentalacademy.com
  2. 2. LIMITATIONS Expensive equipment Single cartridge of resin can be used in one injection molding process, immaterial of lesser or more requirement Poor chemical resistance to strong acids and bases INTRODUCTION  Flexible thermoplastics are resins which offer a conservative and alternative approach to conventional removable partial dentures, by virtue of its flexibility, which utilizes undesired undercuts for retention www.indiandentalacademy.com
  3. 3. LIMITATIONS Expensive equipment Single cartridge of resin can be used in one injection molding process, immaterial of lesser or more requirement Poor chemical resistance to strong acids and bases  Modern dentistry is showing inclination towards flexible material for removable partial dentures (RPDs) because it makes a better and stronger appliance Flexible material reduces the chair side time, eliminates the invasive procedures and provides a prosthesis which is comparatively less bulky, more retentive, more esthetic and to a large extent clinically unbreakable www.indiandentalacademy.com
  4. 4. LIMITATIONS Expensive equipment Single cartridge of resin can be used in one injection molding process, immaterial of lesser or more requirement Poor chemical resistance to strong acids and bases CONCEPT The concept of flexible resins is based on their inherent flexibility and ability to engage hard and soft tissue undercuts for retention Therefore, for clinical cases such as Kennedy's Class I & II, which involve distal extension, the flexible dentures by engaging the severe soft tissue undercuts and clasping the adjacent teeth provides excellent retention www.indiandentalacademy.com
  5. 5. LIMITATIONS Expensive equipment Single cartridge of resin can be used in one injection molding process, immaterial of lesser or more requirement Poor chemical resistance to strong acids and bases Flexible Thermoplastic Resins were discovered 50 years back and are presently gaining popularity, due to improvement in their physical and mechanical properties www.indiandentalacademy.com
  6. 6. LIMITATIONS Expensive equipment Single cartridge of resin can be used in one injection molding process, immaterial of lesser or more requirement Poor chemical resistance to strong acids and bases Flexible resins have some outstanding properties which are as ; They are clinically unbreakable due to their property of shock resistance as well to repeated stressing i.e., under fatigue conditions availability in various tooth and tissue color its lightness flexibility high heat resistance lack of solubility in solvents abrasion resistance high melting point monomer free www.indiandentalacademy.com
  7. 7. LIMITATIONS Expensive equipment Single cartridge of resin can be used in one injection molding process, immaterial of lesser or more requirement Poor chemical resistance to strong acids and bases Flexible denture based on Acetal resin, began to be used in dentistry in 1971 The material in use nowadays is nylon based resin (Lucitone FRS and valplast) Nylon based resin were introduced by W.H Carothers and associates of the Du Pont Chemical Co, during the company’s search for a synthetic fiber forming material www.indiandentalacademy.com
  8. 8. LIMITATIONS Expensive equipment Single cartridge of resin can be used in one injection molding process, immaterial of lesser or more requirement Poor chemical resistance to strong acids and bases Nylon is a generic name for a type of thermoplastic polymers, belonging to the class known as polyamides Polyamide molecules contain the amide group , CONH2 spaced at intervals in a carbon atom www.indiandentalacademy.com
  9. 9. LIMITATIONS Expensive equipment Single cartridge of resin can be used in one injection molding process, immaterial of lesser or more requirement Poor chemical resistance to strong acids and bases There are many types of nylons commercially available which include nylon 6, nylon 4/6, nylon 6/6, nylon 6/10, nylon 6/12, nylon 11 and nylon 12  The ratio of carbon atoms is what gives each nylon type its unique property characteristics www.indiandentalacademy.com
  10. 10. LIMITATIONS Expensive equipment Single cartridge of resin can be used in one injection molding process, immaterial of lesser or more requirement Poor chemical resistance to strong acids and bases The numerical nomenclature for nylon is derived from the number of carbon atoms in the diamine and dibasic acid monomers used to manufacture it e.g., nylon 6,6 in which repeated unit of the polymer chain has two stretches of carbon atoms, each being six carbon atoms long www.indiandentalacademy.com
  11. 11. LIMITATIONS Expensive equipment Single cartridge of resin can be used in one injection molding process, immaterial of lesser or more requirement Poor chemical resistance to strong acids and bases Nylon is formed by two methods that are as follows:  Condensation reaction between diamines and dibasic acids produces a nylon salt. The first number of the nylon type refers to the number of carbon atoms in the diamine, the second number is the quantity in the acid (e.g. nylon 6,12 or nylon 6,6) The second process involves opening up a monomer containing both amine and acid groups known as a lactam ring. The nylon identity is based on the number of atoms in the lactam monomer (e.g. nylon 6 or nylon 12 etc) www.indiandentalacademy.com
  12. 12. LIMITATIONS Expensive equipment Single cartridge of resin can be used in one injection molding process, immaterial of lesser or more requirement Poor chemical resistance to strong acids and bases PROPERTIES Nylons are crystalline and are generally very tough materials with good thermal and chemical resistance The different types of nylon have a wide range of properties with specific gravity, melting point and moisture content depending on nylon number (type), tend to reduce as the nylon number increases Nylon number Specific gravity Melting point Moisture content www.indiandentalacademy.com
  13. 13. LIMITATIONS Expensive equipment Single cartridge of resin can be used in one injection molding process, immaterial of lesser or more requirement Poor chemical resistance to strong acids and bases Nylons tend to absorb moisture from their surroundings and continue to do so until equilibrium state is reached In general, the impact resistance and flexibility of nylon tends to increase with moisture content Nylons tend to provide good resistance to most chemicals, however their property can be effected by strong acids, alcohols and alkalis www.indiandentalacademy.com
  14. 14. COMMON FLEXIBLE THERMOPLASTICS IN USE Materials Composition Manufacturers VALPLAST Hybrid of four nylon Valplast International Corp FLEXITE Nylon based Talladium Uk - dental THERMOFLEX Acetal based resin Austenal LUCITONE FRS Nylon based Dentsply FLEXIPLAST Nylon 12 Polyapress, GMBH, Freiburg, FR Germany www.indiandentalacademy.com
  15. 15. Materials Flexural modulus (MPa) Flexural strength (MPa) Lucitone FRS 1714.4 55.3* Properties of Lucitone FRS www.indiandentalacademy.com
  16. 16. FLEXIPLAST VALUES UNIT Impact strength 1267 J X 10-4 Surface Hardness 387 mm X 10-4 Glass transition Temperature 177.4 0 C Water absorption 1day 1wk 1month 0.71 1.36 1.37 % www.indiandentalacademy.com
  17. 17. LIMITATIONS Expensive equipment Single cartridge of resin can be used in one injection molding process, immaterial of lesser or more requirement Poor chemical resistance to strong acids and bases The material is available in granular form as prepackaged cartridge in various sizes TECHNIQUE Thermoplastic resins are manipulated by injection molding technique to construct flexible dentures Injection molding technique are of two types; manual and the hydraulic www.indiandentalacademy.com
  18. 18. LIMITATIONS Expensive equipment Single cartridge of resin can be used in one injection molding process, immaterial of lesser or more requirement Poor chemical resistance to strong acids and bases Lucitone FRS Resin in prepacked cartridge is heated in cartridge furnace, and then is ready for precision injection This material is used with injection molded system “success” by dentsply Success Injection Unit Heating Furnace www.indiandentalacademy.com
  19. 19. LIMITATIONS Expensive equipment Single cartridge of resin can be used in one injection molding process, immaterial of lesser or more requirement Poor chemical resistance to strong acids and bases Processing time/temp 17 min @ 575o F Injection pressure 75 psi Injection time 1 min Cool time 5 min www.indiandentalacademy.com
  20. 20. LIMITATIONS Expensive equipment Single cartridge of resin can be used in one injection molding process, immaterial of lesser or more requirement Poor chemical resistance to strong acids and bases FINISHING AND POLISHING Special finishing kits are available having cratex wheels, green & pink stones & buff wheels Polish with Tripoli and high shine INSERTION It can be adjusted chair side by immersing the appliance in hot water (1000 C) for a minute and allowed to cool to tolerable mouth temperature prior to insertion www.indiandentalacademy.com
  21. 21. LIMITATIONS Expensive equipment Single cartridge of resin can be used in one injection molding process, immaterial of lesser or more requirement Poor chemical resistance to strong acids and bases ADDITIONAL CLINICAL APPLICATIONS Mouth guards  Bite splints  Gum veneers  Space maintainer Allergic to methacrylate denture base resin www.indiandentalacademy.com
  22. 22. LIMITATIONS Expensive equipment Single cartridge of resin can be used in one injection molding process, immaterial of lesser or more requirement Poor chemical resistance to strong acids and bases  Long term provisional prosthesis during implant or complex restorative cases  Obturators  Patients with restricted mouth opening  For patients prone to breaking dentures It can be used in combination with metal framework as combo dentures www.indiandentalacademy.com
  23. 23. LIMITATIONS Expensive equipment Single cartridge of resin can be used in one injection molding process, immaterial of lesser or more requirement Poor chemical resistance to strong acids and bases ADVANTAGES Strength – fatigue and impact Stiffness Heat resistance Chemical resistance to hydrocarbons Wear resistance Bicompatible – monomer free Flexibility Enhanced retention Unbreakable in clinical conditions Less time required for processing in comparison to conventional www.indiandentalacademy.com
  24. 24. LIMITATIONS Expensive equipment Single cartridge of resin can be used in one injection molding process, immaterial of lesser or more requirement Poor chemical resistance to strong acids and bases Offers the benefit of being strong, thin and lightweight for superior patient comfort Provides esthetics as color blends very well with natural gums since available in many shades Resists stains and bacteria growth Esthetic partial denture Metal free www.indiandentalacademy.com
  25. 25. LIMITATIONS Expensive equipment Single cartridge of resin can be used in one injection molding process, immaterial of lesser or more requirement Poor chemical resistance to strong acids and bases DISADVANTAGES Inability to bond to denture teeth, thus sufficient interridge space is required for bulk of tooth (mechanical retention) Flexibility is not an advantage in complete dentures, as the retentive peripheral seal may break in function  Difficult to repair, add teeth to, or reline www.indiandentalacademy.com
  26. 26. LIMITATIONS Expensive equipment Single cartridge of resin can be used in one injection molding process, immaterial of lesser or more requirement Poor chemical resistance to strong acids and bases Expensive equipment Technique sensitive Poor chemical resistance to strong acids and bases LIMITATIONS www.indiandentalacademy.com
  27. 27. LIMITATIONS Expensive equipment Single cartridge of resin can be used in one injection molding process, immaterial of lesser or more requirement Poor chemical resistance to strong acids and bases CASE REPORT The patient presented with missing 31, 41, 36, 45, 46, 47 www.indiandentalacademy.com
  28. 28. For more details please visit www.indiandentalacademy.com www.indiandentalacademy.com

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