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Denture base materials
- 2. OVERVIEW • History of the denture base material and its change over time • Design requirements and required properties in a denture base material • Current denture base materials in use • Future in denture base materials
- 3. WHAT IS A DENTURE BASE • A denture is made up of two parts; the denture base and the artificial teeth. • A denture base is that part of a denture that makes contact with soft tissue (oral mucosa) and retains the artificial teeth http://www.lemkedent al.com/services_dentur es.html
- 4. HISTORY Egyptians have practiced dentistry since 3000BC. Since 700 BC it has been used to replace teeth. From then on there has been a process in trying to improve the materials.
- 5. WOOD • Wood had been used because it was readily available, inexpensive and could be carved • Nakoka Tei used it in 1538. • Disadvantages are that it cracked in moisture, not aesthetic, unhygienic, and degraded in the mouth. •Tandon,Renu; Gupta,Saurabh; Agarwal, S.K. Denture Base Materials: From Past to Future. Indian Journal of Dental sciences 2010; 2(2): . •Murray,Michael.D;Darvell,Brian.W;. The evoulution of the complete denture base. . Australian Dental Journal 1993; 3(38): . http://museumvictoria.com.au/col lections/items/259128/dental-cast- lower-jaw-plaster-circa-1973
- 6. BONE – PIERRE FAUCHARD • Pierre Fauchard was a pioneer in dental prosthesis in 1678 – 1761. • Fabricated the use of bone by measuring and cutting fit the mouth. • Advantageous because of its availability, reasonable cost, better dimensional stability than wood. • Aesthetic and hygienic concerns were not fulfilled. •Tandon,Renu; Gupta,Saurabh; Agarwal, S.K. Denture Base Materials: From Past to Future. Indian Journal of Dental sciences 2010; 2(2): . •Murray,Michael.D;Darvell,Brian.W;. The evoulution of the complete denture base. . Australian Dental Journal 1993; 3(38): .
- 7. PORCELAIN – ALEXIS DUCHATEAU • Alexis Duchateau (1774) was the first to fabricate porcelain dentures • Advantageous because it could be shaped easily, ensured close contact with the underlying tissues, stable and smooth , less porosity and low solubility • Drawbacks were brittleness and difficulty in grinding and polishing. •Tandon,Renu; Gupta,Saurabh; Agarwal, S.K. Denture Base Materials: From Past to Future. Indian Journal of Dental sciences 2010; 2(2): . •Murray,Michael.D;Darvell,Brian.W;. The evoulution of the complete denture base. . Australian Dental Journal 1993; 3(38): .
- 8. RUBBER – CHARLES GOODYEAR • Charles Goodyear,1839, discovered the process of vulcanization of rubber. • In 1851, Goodyear used this technique to produce a highly cross-linked hard rubber named Vulcanite. • Vulcanite bases were the first functional, durable and affordable dentures. • Disadvantage was their dark red colour , which was difficult to pigment, and absorption of saliva making it unhygienic. •Tandon,Renu; Gupta,Saurabh; Agarwal, S.K. Denture Base Materials: From Past to Future. Indian Journal of Dental sciences 2010; 2(2): . •Murray,Michael.D;Darvell,Brian.W;. The evoulution of the complete denture base. . Australian Dental Journal 1993; 3(38): .
- 9. FROM 1850-1940 • tortoise shell base. • Gutta percha • low fusing silver alloy, bismuth and antimony • Aluminum • Celluloid • Bakelite • Stainless Steel and Metal alloys: Ni-Cr and Co-Cr •Tandon,Renu; Gupta,Saurabh; Agarwal, S.K. Denture Base Materials: From Past to Future. Indian Journal of Dental sciences 2010; 2(2): . •Murray,Michael.D;Darvell,Brian.W;. The evoulution of the complete denture base. . Australian Dental Journal 1993; 3(38): .
- 10. PMMA • Dr Walter Bauer invented the resin. Worked for Rohm and Haas. • Dr. Walter Wright (1937) introduced Polymethyl methacrylate as a denture base material • Major polymer to be used. Kulzer patented the polymerisation process and launched it as Paladon • In 1946, 95 per cent of all denture bases were PMMA. • Had a good stable colour corresponding to the gums, Inert and translucent, reasonably robust, inexpensive and easy to repair. • Additional fibres can increase aesthetic characteristics •Tandon,Renu; Gupta,Saurabh; Agarwal, S.K. Denture Base Materials: From Past to Future. Indian Journal of Dental sciences 2010; 2(2): . •Murray,Michael.D;Darvell,Brian.W;. The evoulution of the complete denture base. . Australian Dental Journal 1993; 3(38): .
- 11. DESIGN REQUIREMENTS FOR A DENTURE BASE MATERIAL
- 12. PROPERTIES Physical Appearance A high Tg temperature Good dimensional stability Low value of specific gravity so that the denture is as light as possible. Thermal conductivity Mechanical High elastic modulus/limit – rigidity Flexural strength to resist fracture Fatigue limit and a high fatigue life. High Impact strength Other Chemically Inert so it is insoluble in oral fluids. Non – toxic and non-irritant to the technician and the patient. Long shelf life and cheap so that it can be bought in bulk and stored without deteriorating.
- 13. DENTURE BASE MATERIALS IN USE Metals Vs Acrylics
- 14. METALS • Gold • Co-Cr alloy • Titanium • Vitallium - alloy of 60% cobalt, 20% chromium, 5% molybdenum. http://www.tedsakamoto dds.com/services • Disadvantages are that they are difficult to adjust and reline. • More accurate than resins. • Cleanliness of the metal base maintains healthy oral tissue unlike some resins. • Metal alloys can be much thinner than resins and still have adequate strength and rigidity. • Thermal conductive as temperature is transmitted through the base maintaining health of the tissue.
- 15. PLASTICS • Acrylic • Polystyrene • Valpast – Flexible dentures http://www.sanforddentalexcellence.com/ar ticles/understanding-the-different-types-of- dentures/ Most commonly used in denture bases. Low TG Low Specific Gravity Low thermal conductivity Poor Impact strength /resistance to fatigue fracture Surface cracks can have a weakening effect on the denture base (crazing). Acrylic slowly absorbs water. Polycarbonates and vulcanite are used in patients allergic to acrylic.
- 16. FUTURE OF DENTURE BASE MATERIALS
- 17. FUTURE Ivobase • self-curing PMMA-based materials/ Fast polymerisation • high precision, quality and efficiency. • Strong bond to the teeth is established. • Safe and clean • No skin contact with the monomer. Predosed – Ideal ratio. •Ivoclar Vivadent. IvoBase Hybrid. http://www.ivoclarvivadent.com/en/ivobase-hybrid (accessed 8 March 2014). Vertex Thermosens • Monomer-free • Virtually no shrinkage: excellent fit • Nylon-derived denture base material • High creep/fatigue resistance • High dimensional stability • Material is light in weight, heat resistant, and ductile. Vertex dental. Vertex Thermosens. http://www.vertex- dental.com/en/products/26-en/26/218-vertex-thermosens (accessed 8 March 2014).
- 18. SUMMARY • Denture bases support the artificial teeth • Denture base materials have an extensive history • The properties required for a denture base are extensive • Current biomaterials are metals and plastics. Two of the most common materials • Future developments build and improve on the history of Denture base materials
- 19. REFERENCES •Alan B. Carr, , David T. Brown. McCracken's Removable Partial Prosthodontics , 12 ed. : Mosby; 2010. •Noort,R.V. Introduction to dental materials, 2nd ed. : Mosby; 1999. •John F. McCabe , Angus Walls . Applied dental materials, 9 ed. : Wiley-Blackwell; 2008. •Ivoclar Vivadent. IvoBase Hybrid. http://www.ivoclarvivadent.com/en/ivobase-hybrid (accessed 8 March 2014). •Vertex dental. Vertex Thermosens. http://www.vertex-dental.com/en/products/26-en/26/218-vertex- thermosens (accessed 8 March 2014). •Tandon,Renu; Gupta,Saurabh; Agarwal, S.K. Denture Base Materials: From Past to Future. Indian Journal of Dental sciences 2010; 2(2): . •Murray,Michael.D;Darvell,Brian.W;. The evoulution of the complete denture base. . Australian Dental Journal 1993; 3(38): .
- 20. ANY QUESTIONS??
Editor's Notes
- The ancient Egyptians have practiced dentistry since 3000BC. In addition, since 700 BC it has been used as a mode to replacing teeth. From then on there has been a process in trying to improve the materials, the aesthetics, function and comfort.
- Wood has been used for years because it was readily available, inexpensive and could be carved to a desired shape. A Buddhist priestess Nakoka Tei used it in 1538. Disadvantages are that it warped and cracked in moisture, aesthetic, unhygienic, and degraded in the mouth.
- Pierre Fauchard was a pioneer in dental prosthesis in 1678 – 1761. He fabricated the use of bone by measuring individual arches with a compass and cutting bone to fit the arch. It was advantageous because of its availability reasonable cost better dimensional stability than wood and carvability. The disadvantages were that the aesthetic and hygienic concerns were not fulfilled.
- Alexis Duchateau (1774) was the first to fabricate porcelain dentures. In 1788, a French dentist, Nicholas Dubois de Chemant, made a baked-porcelain complete denture in a single block. The advantages were that it could be shaped easily , ensured close contact with the underlying tissues, was stable and smooth , less porosity , low solubility but its drawbacks were brittleness and difficulty in grinding and polishing. G.Fonzi an Italian dentist in Paris invented the Porcelain teeth that revolutionized the 1788 A.D. Improvement and construction development of porcelain dentures. Loomis (1854), Charles H Land (1890) and Alexander Gutowski (1962) experimented with porcelain dentures.
- Charles Goodyear, in 1839, discovered the process of vulcanization (converting rubber into more durable compounds by adding sulphur or other groups) of rubber by heating natural rubber (caotachouc), sulphur and white lead together. In 1851, Goodyear used this technique to produce a highly cross-linked hard rubber named Vulcanite after the Roman god. The fit of these vulcanite bases allowed self-retaining dentures, making earlier spring type dentures useless. These were the first functional, durable and affordable dentures, marking a great advancement in dent al treatment . The main disadvantage of these denture bases was their dark red colour , which was difficult to pigment, and absorption of saliva making it unhygienic. Vulcanite dentures were very popular until the 1940s, until acrylic (pink plastic) denture bases replaced them.
- CF Harrington (1850) introduced the first thermoplastic denture material, the tortoise shell base. Gutta Percha (latex) Edwin Truman (1851) used Gutta percha as a denture base but it was unstable. Alfred A Blandy (1856) made dentures from a low fusing alloy of silver , bismuth and antimony but it was never accepted. ALUMINIUM CELLULOID: J. Smith Hyatt (1869) introduced celluloid that was later used as a denture base material because of its translucency and pink colour . However, this material did not gain much popularity because of distortion and discolouration. BAKELITE STAI NLESS STEEL and BASE METAL ALLOYS: Ni-Cr and Co-Cr were obtained by E. Haynes (1907) but they gained popularity after 1937 because of their low density , low material cost, higher resistance to tarnish and corrosion and high modulus of elasticity . Allergy to Nickel and difficulty in adjustment posed a practical problem. VINYL RESIN
- POLYMETHYL METHACRYLATE Dr. Walter Wright (1937) introduced Polymethyl methacrylate as a denture base material which became the major polymer to be used in the next ten years. In 1946, 95 per cent of all denture bases were PMMA. It had a good stable colour corresponding to the gums, Inert and translucent, reasonably robust, inexpensive and easy to repair
- An ideal denture base material should be able to match the appearance of the natural oral soft tissue. The importance of this property depends on whether it is visible when the patient opens their mouth. A high Tg temperature so the base does not distort or soften during use. Although, the patient’s mouth has a temperature of between 32 – 37 degrees they are capable of drinking hot drinks of almost 70 degrees and sometimes-clean dentures in hot water. Good dimensional stability so that the denture does not change over time. This could be due to thermal softening but also internal stresses of the jaw during biting and water absorption, which may lead to instability. Low value of specific gravity so that the denture is as light as possible. Thus, reducing the gravitational displacing forces. Thermal conductivity so that the oral mucosa would remain healthy and so that the patient will have a normal reaction to hot and cold stimuli. If it is a thermal insulator than the patient may drink a drink too hot to bear and so that once it reaches the throat and gut he will fell pain.
- Gold – Inert and is dense, soft and malleable. Co-Cr alloy – Has a very high specific strength Titanium - two most useful properties of the metal are corrosion resistance and the highest strength-to-density ratio of any metallic element. Vitallium - alloy of 60% cobalt, 20% chromium, 5% molybdenum, and other substances. Used in because of its light weight and resistance to corrosion
- Acrylic – Translucent, Good adhesion, Resist cracking and blistering Polystyrene – clear (so can be coloured) , hard and brittle Valpast - Better aesthetics. Good memory, flexible, affordable.