Recent advances in dental materials /certified fixed orthodontic courses by Indian dental academy


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Recent advances in dental materials /certified fixed orthodontic courses by Indian dental academy

  1. 1. GOOD AFTERNOON INDIAN DENTAL ACADEMY Leader in continuing dental education
  2. 2. RECENT ADVANCES IN DENTAL MATERIALS Presented by Dr. A. Premalatha Final M.D.S Dept.Of Prosthodontics
  4. 4. INTRODUCTION The overriding goal of dentistry is to maintain or improve the life of the dental patient . The main challenges for centuries have been the development and selection of biocompatible, long lasting, direct filling tooth restoratives and indirectly processed prosthetic materials that can withstand the adverse conditions of the oral environment.
  5. 5. HISTORY About 3000 B.C Gold bands and wires were used by the Phoenicians (After 2500 B.C) . Around 600 A.D The Mayans used implants consisting of sea shell segments that were placed in anterior teeth sockets. Fauchard (1678-1761) the father of modern dentistry used tin foil and lead cylinders for filling the tooth cavities.
  6. 6. In 1756 Phlip Pfaff of Germany described a method for making impressions . In 1774 Duchateau a French pharmacist designed a process for producing hard , decay proof porcelain dentures. Planteau, a French dentist first introduced porcelain teeth in 1817. In 1839 Charles Goodyear has invented vulcanized rubber denture bases , and in 1935 polymerized acrylic resin was introduced as a denture base material.
  7. 7. CLASSIFICATION Preventive materials Restorative materials Auxiliary materials
  8. 8. IMPRESSION MATERIALS CLASSIFICATION Based on setting mechanism Based on mechanical properties Based on the uses Based on their use in dentistry Based on the amount of pressure applied Based on the manipulation Based on the tray used for impression
  9. 9. Plaster Non-elastic Compound Waxes Impression Materials ZnO - Eugenol Aqueous Hydrocolloids Elastic Agar (reversible) Alginate (irreversible) Polysulfide Non-aqueous Elastomers Silicones Polyether Condensation Addition
  10. 10. AGAR HYDROCOLLOID Indications – crown and bridge high accuracy Example – Slate Hydrocolloid (Van R)
  11. 11. AGAR HYDROCOLLOID COMPOSITION: Agar- 13-17% Borates -0.2-0.5% Sulfates-1-2% Diatomaceous earth, clay, silica Thymol Glycerin Water-85% (sol) (gel) HEAT TO 43degree Agar hydrocolloids (hot) Agar hydrocolloid (cool) HEAT TO 100 degree
  12. 12. Available as -syringe material -tray material
  13. 13. 3-chamber conditioning unit – (1) liquefy at 100°C for 10 minutes converts gel to sol – (2) store at 65°C – place in tray – (3) temper at 46°C for 3 minutes – seat tray – cool with water at 13°C for 3 minutes converts sol to gel
  14. 14. RECENT TECHNIQUES Laminate technique Wet field technique
  15. 15. LAMINATE TECHNIQUE Is the combined agar – alginate technique Tray material- chilled alginate Syringe material –agar Advantages -water cool tray is not required -syringe agar records the tissues more accurately Disadvantages -agar- alginate bond failure. -technique sensitive.
  16. 16. WET FIELD TECHNIQUE The oral tissues are flooded with warm water. The syringe material is injected over the surface to be recorded. Before the syringe material gels tray material placed. The hydraulic pressure of the viscous tray material forces the fluid syringe material down in to the areas to be recorded.
  17. 17. ALGINATE HYDROCOLLOID Most widely used impression material Indications – study models – removable fixed partial dentures framework Examples – Jeltrate (Dentsply/Caulk) – Coe Alginate (GC America)
  18. 18. ALGINATE HYDROCOLLOID COMPOSITION: Potassium alginate -18% Calcium sulphate dihydrate -14% Sodium phosphate -2% Diatomaceous earth or silicate powder -56% Organic glycols Winter green oil Pigments Disinfectants
  19. 19. MANIPULATION Weigh powder Powder added to water – rubber bowl – vacuum mixer Mixed for 45 sec to 1 min Place tray Remove 2 to 3 minutes – after gelation (loss of tackiness)
  20. 20. RECENT DEVELOPMENTS Dust free alginates Siliconised alginates Low dust alginates Antiseptic alginates Color indicating alginates
  21. 21. DUST FREE ALGINATES Dustless alginates contain no dust particles so avoiding dust inhalation. This can be achieved by coating the material with glycerine or glycol. This causes the powder to become more denser than in uncoated state.
  22. 22. SILICONIZED ALGINATES It is a two component system in the form of two pastes, one containing the alginate sol and the second containing the calcium reactor. The components incorporate a silicone polymer component which makes material tear resistant compared to unmodified alginates.
  23. 23. ANTISEPTIC ALGINATES Introduced by Tameyuki Yamamoto, Maso Abinu patented in 1990. o.01 to 7 parts by weight of an antiseptic such as glutaraldehyde and chlohexidine gluconate per 100 parts The antiseptic may be encapsulated in a microcapsule or clathrated in a cyclodextrin.
  24. 24. LOW DUST ALGINATES – Introduced by Schunichi, Nobutakwatanate in 1997. – sepiolite and a tetraflouroethylene resin having a true specific gravity of from 2-3. – The material generates less dust , has a mean particle size of 1-40microns.
  25. 25. COLOR INDICATING ALGINATES Color changes are visualizing the major decision points in impression making -end of mixing time -end of setting time ( tray can be removed from mouth) it indicates two color changes -violet to pink indicates the end of mixing time. -Pink to white indicates end of setting time .
  26. 26. Aqueous Hydrocolloids Elastic Agar (reversible) Alginate (irreversible) Polysulfide Non-aqueous Elastomers Condensation Silicones Polyether Addition
  27. 27. Polysulfide First dental elastomers Indications – complete denture – removable fixed partial denture tissue – crown and bridge Examples – Permlastic (Kerr) – Omni-Flex (GC America)
  28. 28. Composition Base – polysulfide polymers – fillers – plasticizers Catalyst – lead dioxide (or copper) – fillers By-product – water
  29. 29. Manipulation Adhesive to tray Uniform layer – custom tray Equal lengths of pastes Mix thoroughly – within one minute Setting time 8 – 12 minutes Pour within 1 hour
  30. 30. Condensation Silicone Indications – complete dentures – crown and bridge Examples – Speedex (Coltene/Whaledent) – Primasil (TISS Dental)
  31. 31. Composition Base – poly(dimethylsiloxane) – tetraethylorthosilicate – filler Catalyst – metal organic ester By-product – ethyl alcohol Phillip’s 1996
  32. 32. Addition Silicones AKA: Vinyl polysiloxane Indications – – – crown and bridge denture bite registration Examples – – – – – Extrude (Kerr) Express (3M/ESPE) Aquasil (Dentsply Caulk) Genie (Sultan Chemists) Virtual (Ivoclar Vivadent)
  33. 33. Composition Improvement over condensation silicones – no by-product First paste – vinyl poly(dimethylsiloxane) prepolymer Second paste – siloxane prepolymer Catalyst – chloroplatinic acid Phillip’s 1996
  34. 34. Polyether Indications – crown and bridge – bite registration Examples – Impregum F (3M/ESPE) – Permadyne (3M/ESPE) – Pentamix (3M/ESPE) – P2 (Heraeus Kulzer) – Polygel (Dentsply Caulk)
  35. 35. Composition Base – difunctional epimine-terminated prepolymer – fillers – plasticizers Catalyst – aromatic sulfonic acid ester – fillers Cationic polymerization – ring opening and chain extension
  36. 36. RECENT ADVANCEMENTS Hydrophilized addition silicone. with the incorporation of non ionic surfactants as micelles. This increased wettability allows the addition silicones to spread more freely along the surface Miller and coworkers reported modified polydimethyl siloxane wetting agent (extrinsic surfactant)
  37. 37. Recently radiofrequency glow discharge has been advocated for use as a disinfecting procedure for polyvinyl siloxane impressions. Whilst this procedure is claimed to clean and improve the wettability of the impression surface
  38. 38. MONOPHASE IMPRESSION MATERIALS These materials can be used as both light bodied and heavy bodied materials. The amount of pressure given during mixing determines the viscosity. The greater the shear the thinner the viscosity. If more pressure is used it can be used as a light bodied material if less pressure is used it acts as a heavy bodied material.
  39. 39. Visible light cured poly ether urethane Composition includes: -polyether urethane dimethacrylate - diketone – photo initiator - transparent silica – filler (40-60%)
  40. 40. MANIPULATION Transparent stock trays are available. The light bodied material is syringed and the heavy body material is placed above it. Blue light is used for curing. The exposure should be done from the posterior to anterior region. Each region should get an exposure of 30sec.
  41. 41. Advantages: Long working time, but short setting time. Impressions can be corrected. Dimensional stability ,flow, detail reproduction . Disadvantages: Expensive Requires special equipment
  42. 42. LUTING CEMENTS A dental cement used to attach indirect restorations to prepared teeth is called a luting agent . Luting agents may be definitive or provisional depending on their physical properties and the planned longevity of the restoration.
  43. 43. CLASSIFICATIONS Craig’s classification based on the chief ingredients eg: zinc phosphate, zinc silicophosphate, zinc oxide eugenol, zinc polyacrylate, glass ionomer, and resin. O’Brien classified dental cements by matrix and bond type (eg: phosphate, phenolate, poly carboxylate, resin, resin modified glass ionomer) Donovan classified cements into conventional (eg:zinc phosphate,polycarboxylate, glass ionomer) and contemporary (eg:resin modified glass ionomer, resin )
  44. 44. Resin modified glass ionomer (RMGI) Introduced in 1980’s. part of the water component of glass poly alkenoate cement was replaced with a water hydroxyl methyl methacrylate (HMMA) mixture plus an initiator/ activator for the added resins. Resin modified glass ionomer is a dual cure hybrid. The acid base reaction continues to develop a polysalt hydrogel matrix which hardens and strengthens the existing polymer matrix.
  45. 45. COMPOMERS appeared in the late 1990’s, and were described as being a combination of composite resin (comp) and glass ionomer (omer). Compomers are anhydrous resins that contain ion leachable glass as part of the filler and dehydrated poly alkenoic acid. higher compressive and flexural strength than RMGI, but inferior to unmodified composite. Tooth addition is very little , fluoride release is very limited and it’s less than that of conventional glass ionomer .
  46. 46. RESINS Resin cements are methyl- methacrylate, BisGMA dimethacrylate or Urethane dimethacrylate based with fillers of colloidal silica or barium glass 20-80% by wt. They are available as powder/liquid, encapsulated or paste/paste systems and may be auto, dual or light cured to form the polymer matrix. Resin bonding to enamel is by mechanical interlocking into an acid etched surface.
  47. 47. ADHESIVE RESINS In the early 1980’s conventional Bis GMA resin cement was modified by adding a phosphate ester to monomer component. Eg; Panavia – contained the bifunctional adhesive monomer 10- methacryloyloxy deci dihydrogen phosphate (MDP) and was a powder/ liquid system the current product Panavia F is a two paste system that is dual cured , self etching and self adhesive plus fluoride releasing
  48. 48. Dong xie, Youfun yang et al had developed a novel comonomer free light cured glass ionomer system based on 4 arm star shape poly acrylic acid. has significantly improved mechanical strength, and no invitro cytotoxicity observed.
  49. 49. GC America announces Fuji CEM Automix , the first automix delivery system available in a resin modified glass ionomer. Fuji CEM Automix requires no hand mixing and dispences a consistent mixing ratio directly into the restoration.
  50. 50.
  51. 51. Def: An inorganic compound with nonmetallic properties typically consisting of oxygen and one or more metallic or semimetallic elements (eg: aluminium, calcium, lithium, magnecium, potassium, silicon, sodium , tin, titanium and zirconium) that is formulated to produce the whole or part of a ceramic based dental prosthesis
  52. 52. HISTORY The porcelain tooth material was patented in 1789 by French dentist de Chemant in collaboration with a French pharmacist Duchateau. In 1808, Fonzi an Italian dentist invented a terrometallic porcelain tooth that was held in place by a platinum pin or frame. Planteau, a French dentist introduced porcelain teeth to united states in 1817 and Peale an artist. Ash developed an improved version of the porcelain tooth in 1837. Dr Charles land introduced one of the first ceramic crowns to dentistry in 1903
  53. 53. Pressable glass ceramic (IPS Empress ) was introduced in early 1990’s, A more fracture resistant, pressable glass ceramic (IPS Empress 2) was introduced in the late 1990’s.
  54. 54. CLASSIFICATION Based on chemical composition Based on crystalline nature Based on fusion temperature Based on type Based on the method of fabrication Based on application Based on sub structural material Based on use Based on firing Classification based on recent types of ceramics
  55. 55. Classification based on recent types of ceramics – castable glass ceramics eg: Inceram, alumina, Inceram, spinell – pressable ceramics EG: Optec HSP, IPS empress – CAD – CAM ceramics eg: cere vitablock markI, vitablock mark II – Injection molded ceramics eg: Optec HSP
  56. 56. Castable glass ceramics – EG Inceram, alumina, Inceram, Spinell, Dicor and Dicor MGC – Castable ceramic systems are used to cast crowns by the lost wax process. – Indicated in cases of single anterior and posterior crowns – An ingot of the ceramic material is placed in a special crucible and melted and cast with a motor driven centrifugal casting machine at 1380 degree C.
  57. 57. Hot pressing Eg: IPS Empress, IPS Empress 2, IPS e max press, OPC pressure molding is used to make small intricate objects . IPS Empress is a glass ceramic provided as core ingots that are heated and pressed until ingot flows in to a mold. It contains a higher conc. of leucite crystals that increase the resistance to crack propagation (fracture).
  58. 58. Machinable ceramics Computer aided design / computer aided manufacturing There are two popular systems available for machining all ceramic restorations -CEREC System (siemens, Bensheim, Germany) -Celay system (Mikrona technologies, Switzerland)
  59. 59. CEREC SYSTEM HISTORY: It was introduced by Werner H.Mormann (1980) at the university of Zurich. The first chair side CEREC introduced in 1985. In 1994 CEREC -2 was introduced. In 2000 CEREC -3 was introduced. In 2003 , 3D soft ware version is released, allowing users to see 3D views of teeth and models In 2008, Sirona release the MCXL milling unit , this milling unit can produce a crown in 4 minutes.
  60. 60.
  61. 61. CEREC - I introduced in 1985 chief indications are single dual surface inlays and material is vitablocs markII and the The concept of grinding inlay bodies externally with a grinding wheel along the mesiodistal axis suggested itself.
  62. 62. CEREC - II – introduced in 1994 – additional cylinder diamond enabling the form grinding of partial and full crowns. – An upgraded 3D camera was provided.
  63. 63. CEREC - III skipped the wheel and introduced the two bur system. It’s a compact windows based CAD- CAM system
  64. 64.
  65. 65. CELAY system The celay system (Mikrona technologie, spreitenbach, Switzerland) uses a copy milling technique to manufacture ceramic inlays or onlays from resin analogs. The Celay system is a mechanical device based on pantographic tracing of a resin inlay or onlay fabricated directly on to the prepared tooth or on to the master die (Eidenbenze U/1994).
  66. 66.
  67. 67. DENTURE BASE RESINS Poly (methyl methacrylate) polymers were introduced as denture base materials in 1937. previously used materials: vulcanite , nitrocellulose, phenol formaldehyde, vinyl plastics and porcelain
  68. 68. CLASSIFICATION Based on the duration of use Based on the material used Based on the chemical composition of the resins Types of acrylic resins -based on their mode of activation -based on filler particles
  69. 69. EVOLUTION Acrylic acid and its derivatives came to be well known by the 1890’s Dr.ottorohm is considered as the father of Recent acrylic. He introduced polymers of acrylic acid in 1901. 1927 acryloid and plexigum both polymers polymethylmethacrylate were introduced by Rohm and Haas. of In 1931 commercial production of harder poymethyl methacrylates occurred with the introduction of plexiglass (also known as organic glass, leucite I plexite) Acrylic resins came in to use in dentistry between 1930 and 1940. they are used in dentistry as denture base materials.
  70. 70. RECENT ADVANCEMENTS Pour type acrylics High impact strength acrylics Rapid heat polymerized acrylics Light activated acrylics Reinforced denture base materials
  71. 71. Pour type acrylics The principle difference is in the size of the polymer powder or beads. smaller powder particles, when mixed with monomer the resulting slurry is very fluid. The mix is quickly poured in to an agar hydrocolloid or modified plaster mold and allowed to polymerze under pressure at 0.14MPa. Centrifugal casting and injection molding are technique s used to inject the slurry into the mold.
  72. 72. High impact strength acrylics These polymers are reinforced butadiene –styrene rubber. with These materials are supplied in a powderliquid form and are processed in the same way as other heat accelerated methyl methacrylate materials.
  73. 73. Rapid heat polymerizing acrylics The initiator is formulated from both chemical and heat activated initiators to allow rapid polymerization without the porosity. After placing the denture in boiling water the water is brought back to a full boil for 20min.
  74. 74. Light activated acrylics This denture base material consists of a urethane dimethacrylate matrix with an acrylic copolymer , microfine silica fillers and a photoinitiator system. It’s supplied in premixed sheets having a clay like consistency. The denture base material is adapted to the cast while it’s still pliable The denture base can be polymerized in a light chamber with blue light of 400-500nm.
  75. 75. Reinforced denture base resins Glass fillers Carbon / graphite fillers metal fillers Aramid fillers Polymer fiber composites Ultra high modulus polyethylene fibers (UHMP). Aluminium oxide addition
  76. 76. Introduction of a denture injection system for use with microwavable acrylic resins
  77. 77. In the GC INJECTION system a pneumatic press is used to force unpolymerized acylic resin into the mold cavity. A modified microwavable flask is used to facilitate this process . The modified flask has a small channel in its lid that permits a small diameter sprue (7mm)to pass from the external surface of the flask in to the mold cavity.
  78. 78. Development of a radio-opaque auto polymerizing dental acrylic resin There are many materials which can act as radio opaque additives eg;Barium sulfate, Barium acrylate, Bismuth bromide Patrik A..Mattie et al (1994) proposed a component that is Triphenyl Bismuth has a very low level of cytotoxicity which indicates significant biocompatibility.
  79. 79. CONCLUSION It is the goal of medical procedure to provide the best treatment for the patient while following the Hippocratic oath: “First , do no harm”. As dentists , we are challenged to restore function while providing a highly esthetic result . An examination of material properties should lead us to select those systems engineered to provide the patient with best clinical out come with respect to esthetics , function , longevity and compatibility with surrounding natural tissues.
  80. 80. REFERENCES Restorative Dental materials:G Craig & John M Powers-11th edition2002. Phillips science of dental materials: Anusavice; 11th edition DCNA, July 2007, 994-1003. O’Brien, Dental Materials & their Selection 1997 Evolution of dental ceramics in the twentieth century, John W.Mclean, JPD VOL-85, NO.1, Jan-2001. A novel comonomer –free light-cured glass – ionomer cement for reduced cytotoxicity and enhanced mechanical strength. Dong Xie, J of Dental materials 23 (2007) 994-1003. The effect of disinfection and a wetting agent on the wettability of addition silicone Impresion materials; Paul J.Milward, JPD 2001; 86.165-7.
  81. 81. Introduction of a denture injection system for use with microwaveable acrylic resins; R,D Phoenix, JOP, V ol 6, No.4, DEC1997, pg286-291. JOP , 2004,VOL13, NO.2(june), pg 83-89 JOP; VOL-2, No.3 ,sept 1993; pg 174-177 JOP; VOL-3,No.4 DEC.1994;pg 213-218 Poly vinyl siloxane impression materials ; an update on clinical use; Michael N.Mandiko; Australian dental journal ,1998, 43 (6); 428-434. JOP; xx (2008) 1-6 JOP; VOL-5, No.4 DEC,1996, PG 270-76 JOP; VOL-8, No.1 march 1999, pg 18-26 Clinical performance of chair side CAD/CAM restorations;JADA, VOL 137, 22-31 The evolution of the CEREC system; Werner H. Mormann, JADA, vol 137, 2006 Materials for chairside CAD/CAM produced restorations, Russell GIORDANO;JADA, vol 137 ,2006 14
  83. 83.