What Is Denture Repair-it Liquid Made Of

Denture Base Resin

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ane. Denture Base Resin -Dr. Soham Prajapati 1st Yr Postal service Graduate, Dept. of Prosthodontics & Maxillofacial Prosthesis Including Oral Implantology. 7/12/2013 & 9/12/2013 1
2. • Definition • History • Classification • Dental polymers • Ideal requirements of Denture Base Resin • Main ingredients of Denture Base Resin • Dissimilar Types Denture Base of operations Resins • Properties of PMMA • Cytotoxicity of Denture Base Acrylic Resins • Contempo Advances • Decision • References 2
3. Definition • DENTURE BASE: The office of a denture that rests on the foundation tissues and to which teeth are attached. • RESIN: A broad term used to describe natural or constructed substances that grade plastic materials after polymerization. - GPT eight 3
4. Key Points of DENTAL RESINS • ADA/ANSI Specification no 12 - Denture base of operations resins. • ISO 1567 four
5. History • Skillfully designed dentures were made as early as 700 BC using ivory and os. • Till 1800s, dentures were paw carved and tied in place with silk threads. • Queen Elizabeth I and George Washington suffered from tooth loss and unfit dentures. 5
half-dozen. History • In 1774, Duchateaus and Dubois de Chemant designed a full set of dentures that would non rot.(made of porcelain.) 6
7. History • Giuseppangelo Fonzi created a single porcelain tooth held in place past a steel pivot in 1808. • Claudius Ash made an improved porcelain tooth in 1837. • Porcelain dentures moved to United states in 1800s and marketed on a big scale. Fit was eventually improved as well. 7
8. History • In 1700s, plaster of paris was introduced. It was used to make a mold of the patient's rima oris. This helped to make the dentures precise. • Swaged Gilt was used equally denture base of operations for those who could afford it. 8
nine. • Real breakthrough when vulcanized safety was discovered by Charles Goodyear in 1840. – Cheap – Like shooting fish in a barrel to piece of work – Hold the denture • Vulcanite dentures were available in Bharat under British dominion by British and other European Dentists. History 9
10. Vulcanite • Contains 32 % sulphur and metallic oxides for color. Advantages Disadvantages Nontoxic Non-irritant Excellent Mechanical Backdrop Quiet hard to smooth Absorbs Saliva Becomes unhygienic. Unpleasant odor(when processed) Poor esthetics (opacity of condom) Dimensional changes. 10
xi. Nitrocellulose • Dimensionally stable • Excessive Warpage • High water absorption • Poor colour stability • Contains unpleasant tasting plasticizer • Highly flammable eleven
12. Other • Celluloid – Was tried in place of prophylactic but didn't prove best of the material. • Porcelain – It was tolerate past denture bearing mucosa, just difficult to fabricate and hands broken. • Phenol Formaldehyde – Becomes dicolored and unesthetic and beingness thermosetting, it is difficult to repair 12
13. History • In 1937 Dr. Walter Wright gave dentistry its very useful resin. • It was polymethyl methacrylate which proved to be much satisfactory material tested until now. • By 1946, 98% of all denture bases were fabricated from PMMA. 13
14. Classification • Co-ordinate to ISO 1567 – Type 1 • Class 1 Heat processing polymers, powder and liquid • Class two Heat candy (plastic cake) – Type 2 • Class i Autopolymerized polymers, powder and liquid • Grade 2 Autopolymerized polymers (powder and liquid pour type resins) – Blazon 3 Thermoplastic blank or powder – Type iv Low-cal Activated Materials – Blazon 5 Microwave-Cured Textile 14 Practical Dental Materials, 8th edition, John F McCabe & Angus West. G. Walls
15. Classification • Based on the usage:- – Temporary Denture Base Resin • E.g. Self Cure Acrylics • Shellac base plate • Base plate wax • Injection Molded resins • Metallic Bases – Permanent Denture Base of operations Resin • E.g. Heat Cure Denture Base • Low-cal Cures Resins • Cascade Blazon Resins 15
16. Classification • Based on the METHOD USED FOR ITS ACTIVATION:- – Chemically activated – Oestrus activated – Light activated 16
17. DENTAL POLYMERS • Polymer is chemical compound consisting of large organic molecules formed by the spousal relationship of many repeating smaller monomer units. 17
18. • Polymerization occurs through a series of chemic reactions by which the macromolecule, or the polymer, is formed from big numbers of molecules known equally monomers. • TYPES:- – CONDENSATION POLYMERIZATION – Improver POLYMERIZATION 18
19. CONDENSATION POLYMERIZATION • TWO GROUPS – Those in which polymerization is accompanied by repeated elimination of small molecules. The process repeat itself and form macromolecules. E.yard. h2o, element of group vii acids, ammonia, etc. xix
20. – Those in which functional groups are repeated in the polymer chains. The polymers are joined by functional groups. Germination of a by-product is not necessary. E.k. polyurethane. Not widely used in DENTISTRY 20
21. ADDITION POLYMERIZATION • All resins employed extensively in dental process are produced by improver polymerization. • No alter in chemical composition and no past- products are formed. 21
22. How?? • Starting from an active heart, one molecule at a time is added and a chain apace builds upward, which can abound virtually indefinitely equally long as the supply of building blocks are available. 22
23. Chemical Stages of Polymerization 4 Stages:- • Consecration • Propagation • Chain Transfer • Termination 23
24. Induction • Induction or initiation menses is the fourth dimension during which the molecules of the initiator becomes energized or activated and start to transfer the energy to the monomer. 24
25. • Three induction systems:- – Heat Activation – Chemic Activation – Light Activation • Estrus Activated:- The gratis radical liberated by heating benzoyl peroxide will initiate the polymerization of methyl methacrylate monomer. e.g. Denture base Resins 25
26. • Light Activated:- – Photons of calorie-free energy activate the initiator to generate gratuitous radicals. e.g. blended resin. Chemic Activated:- – System consists of at least two reactants, when mixed they undergo chemical reaction and liberate complimentary radicals, east.yard. Cocky Cured Resin 26
27. INDUCTION 27
28. INDUCTION 28
29. 29
xxx. PROPAGATION • In one case the growth has started, the process continues with considerable velocity. • Theoretically, the chain reactions should keep with evolution of heat until all the monomer has been changed to polymer. • Actually, the polymerization is never consummate. 30
31. PROPAGATION 31
32. 32
33. Concatenation TRANSFER • The concatenation termination can also result from chain transfer. Here, the activated land is transferred from an activated radical to an inactive molecule, and a nucleus of growth is created. 33
34. CHAIN TRANSFER 34
35. CHAIN TRANSFER 35
36. TERMINATION • The chain reaction tin exist terminated either by directly coupling or by exchange of hydrogen atom from one growing chain to some other. 36
37. Termination 37
38. Termination 38
39. 39
xl. COPOLYMERIZATION • The macromolecule may be formed by polymerization of a single type of structural unit. • In club to meliorate the concrete backdrop, it is often advantageous to use two or more chemically different monomers equally starting materials. forty
41. • The polymer thus formed may contain units of these monomers. Such a polymer is chosen a copolymer and its process of germination is known as copolymerization. 41
42. Types of COPOLYMER • There are iii different types:- • RANDOM Blazon • GRAFT TYPE • Cake Type 42
43. RANDOM TYPE • In random type of copolymer the different monomers are randomly distributed along the chain. ……ABBABABAAAAAABBABABABBBBBABBABBAB…. 43
44. GRAFT TYPE • Sequence of one of the monomers are grafted onto the 'backbone' of the second monomer species. 44
45. • Identical monomer units occur in relatively long sequences forth the principal polymer chain. …..AAAAABBBBBAAAAABBBBBAAAAABBBBBAAAAA….. Cake Blazon 45
46. IMPORTANCE OF COPOLYMERIZATION • It is to meliorate the concrete properties of resins. • Many useful resins are manufactured by copolymerization. 46
47. CROSS-LINKING • The germination of chemical bonds or bridges betwixt the linear polymer is referred to equally Cantankerous-LINKING. • It forms a 3-dimensional (3D) network. 47
48. Application Of Cantankerous-Linking • The more recent acrylic resins are of cross- linked variety. It improves the strength, and decreases the solubility and water sorption. • Acrylic teeth are highly cross-linked to improve its resistance to solvents, crazing and surface stresses. 48
49. Requirements Of Denture Base Materials 49
50. ADA Specification Full general Requirements of the non-candy Materials Liquid Clear as Water Free of Extraneous Material 50
51. Specification Full general Requirements of the not-processed Materials POWDER, PLASTIC Cake OR PRECURED BLANK Costless OF IMPURITIES SUCH AS DIRT AND LINT 51
52. Full general REQURIMENTSREQUIREMENTS Inside 5 MINUTES , Later on REACHING THE PROPER CONSISTENCY, INDICATED BY CLEAN SEPERATION FROM THE WALLS OF Drinking glass MIXING JAR & THE Material SHOULD Take ADEQUATE FLOW PROPERTY WATER SORPTION SHALL Not BE MORE THAN 0.viii mg/cm2 Later IMMERSION FOR 7 DAYS AT 37° C SOLUTIBILITY SHALL NOT Be More than 0.04 mg/cm2 AFTER THE Water SORPTION SPECIFIC IS Stale TO Constant WEIGHT 52
53. GENERAL REQURIMENTSREQUIREMENTS THE PLASTIC SHALL SHOW NO MORE THAN A SLIGHT COLOUR CHANGE WHEN EXPOSED 24 HOURS TO A SPECIFIED ULTRAVIOLET LAMP TEST. THE TRANSVERSE DEFLECTION SHALL BE Within THE LIMITS LISTED IN THE Give-and-take. 53
54. 54
55. Ideal Requirements Of Denture Base Materials Last study of the workshop on clinical requirements of ideal denture base material one. Physiologic compatability • Nontoxic • Noncarcinogenic • Nonallergenic • Compatible with physiologic requirements of mucous membranes Optimum consistency to maintain or promote tissue health • Not deleterious to adjacent and underlying tissues • Conducive to normal salivary catamenia 55ATWOOD:JPD 1968 (20) 101-105
56. 2. Acceptability to patients' senses • Acceptable to all five senses-sight, sound, olfactory property, gustatory modality, and bear on • Able to duplicate and simulate oral tissues as nearly every bit possible • Possessing wide choice of color • Possible for esthetics to be easily modified • Color stable • Odorless • Tasteless • Possessing instantaneous temperature conductivity • Lite weight • Possessing sensation of natural texture 56
57. 3. Functional usefulness • Rigid enough so that teeth penetrate the bolus • No interference with oral functions of chewing, swallowing, self cleansing, singing, voice communication, sneezing, breathing, laughing, coughing, etc. 57
58. 4. Hygienic factors • Sterilizable • Resistant to stain, calculus, and adherent substances • Nonporous to microorganisms • Low fluid absorption • Wettable (low surface tension) • Hands cleaned 58
59. 5. Durability • Not afflicted past oral environment-bacteria, food, medicines, etc. Unbreakable (not brittle) • Not crazing • Dimensionally stable and statically stable • Minimal internal strain • Skillful bond between different base materials • Good bond betwixt base and teeth • Not flammable • Resistant to weak acids and alkalis • Resistant to abrasion and vesture • Resistant to strain • Long lasting 59
threescore. 6. Adaptability to clinical problems • Adjustable • Easily polished • Hands repaired • Easily relined • May demand more than ane type of cloth • May utilise combinations of materials (soft for tissues, hard for teeth) Choice of hardness or softness (various materials for unlike situations 60
61. 7. Toll factors • Unproblematic to manipulate • Simple to process • Inexpensive equipment for processing Average skill required for processing No separation medium required Easily separated from bandage • Moderate cost of fabrication • Proficient shelf life • Predictable properties 61
62. PRINCIPAL INGRIDIENTS OF DENTURE Base of operations RESIN 62
63. Primary INGREDIENTS OF ACRYLIC DENTURE Base RESIN Pulverisation LIQUID Acrylic polymer (or Copolymer) chaplet Initiator Pigments Dyes Opacifiers Plasticizer Dyed organic fibers Inorganic particles Monomer Inhibitor Accelerator Plasticizer Cantankerous-linking amanuensis 63CRAIG RESTORATIVE DENTAL MATERIAL
64. Acrylic Resins used In Dentistry • Derivatives of Ethylene and contains a vinyl grouping in their structural formula. • Acrylic resin used in dentistry are the esters of :- – Acrylic acid, CH2 = CHCOOH – Methacrylic acid, CH2 = C(CH3)COOH 64
65. DENTURE Base RESINS Oestrus ACTIVATED DENTURE Base of operations RESINS • Near widely used resins for the fabrication of complete dentures. • Available as:- – Pulverization and liquid • Powder may exist transparent or tooth colored or pinkish colored (to stimulate the mucilage, some fifty-fifty contain reddish fibers to duplicate claret vessels). • Monomer is supplied in tightly sealed amber colored bottles (to prevent premature polymerization by light or ultraviolet radiations on storage). 65
66. • Commercial Names:- – Stellon (DPI) – Lucitone (Bayer) – Travellon (Dentsply) 66
67. Composition 67 Pulverisation Poly (methyl methacrylate) Ethyl or butyl Methacylate (5 %) Benzoyl Peroxide Compounds of Mercuric sulfide, cadmium sulfide, etc. Zinc or titanium oxide Dibutyl phthalate Inorganic fillers similar glass fibers, zirconium silicate, alumina, etc. Dyes synthetic nylon or acrylic fibers Major component Copolymers – improved properties Initiator Dyes Opacifiers Plasticizer Improves physical properties like stiffness, etc. To simulate small capillaries
68. Composition 68 LIQUID Methyl methacrylate Dibutyl phthalate Glycol Dimethacrylate Hydroquinone (0.006%) Plasticizes the polymer Plasticizer Cross-Linking agent (reduces Crazing) Inhibitor – prevents premature polymerization
69. 69 Chemical Basis
seventy. 70 POLYMER POWDER OF ACRYLIC DENTURE Base of operations MATERIAL
71. TECHNIQUE • Primary impressions • Secondary impressions • Jaw relations • Endeavour in phase • Acrylization – Flasking – Dewaxing – Packing- under pressure – Curing 71
72. Flasking • The Fine art of Investing in a Flask " - GPT • Flask " a metallic instance or tube used in investing process" - metal - brass - three or iv parts 72
73. 73 iii Office FLASK
74. 4 PART FLASK 74
75. Pressure Clench 75
76. FLASKING 76 3 Cascade TECHNIQUE 4 POUR TECHNIQUE
77. Compression MOLDING TECHNIQUE  Periphery of flask should be in level with the rim of the flask  Occlusal plane – parallel to the base of the flask 77
78. • Tilting of the casts • Retromolar pads and tuberosity should exist protected • Checking the seating of flask members • Distance from top lid – vi mm 78
79. • Paint on separating media similar cellulose lacquers, solution containing alginate compounds, calcium oleate ,soaps, sodium silicate, starches were introduced….. Tin foil substitutes. • Almost popular… water soluble alginate solution • Produce thin, relatively insoluble calcium alginate films….. 79
80. Sodium Alginate Solution • Water soluble. • Reacts with the calcium of plaster or stone to grade a flick of insoluble calcium alginate. • Limerick – 2 % sodium alginate in water – Glycerine – Booze – Sodium phosphate – Preservatives 80
81. Sodium Alginate Solution • Application – Applied using castor, blanket only the plaster surfaces. – One or two coats are practical. 81
82. Sodium Alginate Solution • Precautions to exist taken – Waxes or oils remaining on the mold surface will interfere with the action of the separating medium. – Mold should not be warm, not hot. Continuity of the film will break if the mold is steaming hot. – Avoid coating on teeth. 82
83. • Second mix is mixed • Lid is closed • Flask is clamped 83
84. Polymer – Monomer Interaction • Sandy, stringy, dough like, rubbery or elastic, stiff • During sandy stage, trivial or no interaction occurs on a molecular level. Polymer beads remain unaltered. • Later, mixture enters stringy stage. Monomer attacks the surfaces of individual polymer beads. Stage characterized by stringiness. 84
85. Polymer – Monomer Interaction • Afterwards the mass enters a dough like phase. On molecular level increased number of polymer chains are formed. Clinically the mass becomes as a pliable dough. Information technology is no longer tacky • This stage is ideal for compression molding. • Hence fabric is inserted into mold cavity during dough like phase. 85
86. • Post-obit dough like stage, the mixture enters rubbery or rubberband stage. Monomer is dissipated by evaporation and past farther penetration into remaining polymer beads. In clinical use the mass rebounds when compressed or stretched. • Upon standing for an extended period, the mixture becomes potent. This may be attributed to the evaporation of free monomer. From clinical point, the mixture appears very dry and resistant to mechanical deformation 86
87. DOUGH FORMING Fourth dimension • The time required for the resin mixture to reach a dough like stage is termed the dough forming time. • In clinical apply, the majority of resin reach a dough like consistency in less than 10 min. 87
88. PACKING • Placement and adaptation of denture base of operations fabric within the mold cavity is termed packing. Over packing- leads to excessive thickness and malposition of prosthetic teeth Nether packing- leads to noticeable denture base porosity • Trial packing is washed to ensure proper packing of resin mass in the mold. • After the final closure of the flasks, they should remain at room temperature for 30- 60 min. it is chosen bench curing 88
89. Bench curing • It permits equalization of force per unit area throughout the mold • Allows more than time for uniform dispersion of monomer throughout the mass of dough • If resin teeth are used, information technology provides a longer exposure of resin teeth to the monomer producing a better bail of the teeth with the base cloth 89
90. POLYMERIZATION PROCEDURE / CURING • When heated above 60 °C, molecules of benzoyl peroxide decompose to yield free radicals. • Each free radicals, rapidly reacts with an available monomer molecule to initiate polymerization. • Heat is required to cause decomposition of benzoyl peroxide. Therefore heat is termed as activator. • Decomposition of benzoyl peroxide molecule yields complimentary radicals that are responsible for initiation of concatenation growth. Hence it is termed equally initiator ninety
91. Temperature rise • Because resin and dental stone are relatively poor thermal conductors, the heat of reaction cannot be dissipated. Therefore the temperature of resin rises well higher up the temperature of investing stone and surrounding water. • It should be noted that temperature of resin non allowed to exceed the boiling bespeak of the monomer (100.8oC) – which produces pregnant furnishings on the concrete characteristics of the processed resin. 91
92. Curing cycle • Following curing cycle take been quite successful – Processing in a abiding temperature h2o bath at 74oC for 8 hours or longer with no terminal boil. – Processing in a 74 0C h2o bath for 8 hours and then increasing the temperature to 100oC for 1 hr. – Processing resin at 74oC for approximately 2 hours and increasing the temperature of water bathroom to 100oC for 1 hour. 92
93. Polymer – Monomer Ratio • Polymerization of MMA to PMMA yields 21% decrease in the book of material, which would create difficulties in denture base fabrication and clinical utilize. • To minimize dimensional changes, Resin manufacturers prepolymerize a significant fraction of the denture base resin. • The accepted polymer to monomer ratio is 3:1 by book. • Using this ratio the volumetric shrinkage is limited to 6% and 0.v% linear shrinkage. 93
94. Polymer – Monomer Ratio 94 If too much monomer is use:- If as well piddling monomer is use:- Greater curing or polymerization shrinkage More time is needed to reach the packing consistency Porosity may occur in denture Not all the polymer bead will be wetted past monomer and the cured acrylic will be granular. Dough volition exist difficult to manage and it may not fuse into a continuous unit of measurement of plastic during processing
95. • First reported by Kimura et. al • This technique employs a particularly formulated resin and a non metallic flasks. FRP Flask [ Fiber Reinforced Plastic flasks] 95 POLYMERIZATION VIA MICROWAVE ENERGY
96. Advantages: • Cleaner and faster polymerization. 3 minutes • Minimal color changes • Less fracture of artificial teeth and resin bases • Superior denture base adaptability 96
97. • No noticeable difference • Trade name – Keystone Diamond D • Disadvantages Flasks are expensive and take trend to break down after processing several dentures. The polycarbon bolts tend to break if tightened too firmly. 97 Bernard Levin et al [ JPD 1989;61: 381-383]
98. Injection molded polymers • In mid 1970'due south, Ivoclar introduced this system. • These are fabricated of Nylon or Polycarbonate. • It has to be heated and injected into a mold 98 The SR-Ivocap system uses specialized flasks and clamping presses to keep the molds under a constant pressure of 3000 lbs
99. Injection molded polymers • Flask is and then placed into h2o bath for polymerization every bit the material polymerizes addition resin is introduced into the mold cavity. This process offsets the effects of polymerization shrinkage. • Equipment is expensive. 99 The SR-Ivocap system uses specialized flasks and clamping presses to keep the molds under a constant pressure of 3000 lbs
100. Injection molded polymers • Advantages – Dimensional Accuracy – No increase in vertical dimension. – Homogenous denture base of operations – Low free monomer content – Expert impact strength • Disadvantages – High toll of equipment – Difficult mold design – Less craze resistant – Special flask is required. 100
101. 101
102. Technique 102
103. Technique 103
104. Chemically Activated Denture Base Resins • Does not require thermal energy. • Hence often referred to as cold curing, self curing or autopolymerizing resins. 104
105. Chemically Activated Denture Base Resins • Chemical activation is achieved through the add-on of a tertiary amine such equally dimethyl- Para- toluidine to the liquid. • Upon mixing, the tertiary amine causes decomposition of benzoyl peroxide. Consequently, gratis radicals are produced and polymerization is initiated. 105
106. Composition 106 POWDER Poly (methyl methacrylate) and other co-polymer(5 %) Benzoyl Peroxide Compounds of Mercuric sulfide, cadmium sulfide, etc. Zinc or titanium oxide Dibutyl phthalate Dyes organic fillers and inorganic particles like glass dewdrop fibers or beads. Dissolves the monomer to form dough Initiator Dyes Opacifiers Plasticizer Esthetics
107. Limerick 107 LIQUID Methyl methacrylate Dimethyl-p-toluidine Dibutyl phthalate Glycol Dimethacrylate 1 to two% Hydroquinone (0.006%) Dissolves/Plasticizes the polymer Activator Plasticizer Cross-Linking amanuensis (reduces Crazing) Inhibitor – prevents premature polymerization
108. MANIPULATION OF AUTOPOLYMERIZATION RESINS • Sprinkle on technique • Adapting technique • Fluid resin technique • Compression molding technique 108
109. • There is greater amount of unreacted monomer which creates ii major difficulties. 1. It acts as plasticizer that results in decreased transverse strength of denture resin. 2. Residual monomer serves equally a potential tissue irritant, thereby compromising the biocompatibility of the denture base. 109
110. Technical considerations • Most often molded using pinch technique. • Mold grooming and resin packing are essentially same. • Working time for self cure resin is shorter than heat cured resins. • Refrigerating the liquid component or mixing vessel before mixing process tin can prolong the working time. 110
111. Processing considerations • Post-obit concluding closure of the denture flask, pressure must exist maintained throughout polymerization process. • Initial hardening of resin occurs within 30 minutes of final closure. • To ensure sufficient polymerization, the flask should be held under pressure for minimum 3 hours • Resins polymerized via chemical activation generally brandish 3-5% free monomer where as heat activated resins 0.2-0.5% free monomer. 111
112. Uses • Temporary crowns and FPDs. • Construction of special tray. • For denture repair, relining and rebasing. • Making removable orthodontic appliances. • For adding a post dam to an adjusted upper denture. • For making temporary and permanent denture bases. 112
113. FLUID RESIN TECHNIQUE • Special resin is available. • Chemical composition is like to polymethyl methacrylate materials. • Principal deviation is they have high molecular weight powder particles that are much smaller and when they are mixed with monomer, the resulting mix is very fluid. • Significantly lower ability: liquid ratio ranges from two:1 to ii.5:1. 113
114. Method of Flasking and Curing • Agar hydrocolloid is used for the mold preparation in identify of the usual gypsum. • Fluid mix is rapidly poured into the mold and allowed to polymerize under pressure at 0.14 MPa . 114
115. Fluid Resin Technique • Employs a pourable chemically activated resin Advantages • Improved adaptation to underlying soft tissues. • Decreased damage to prosthetic teeth and denture base of operations during deflasking. • Reduced material costs. • Simplification of flasking, deflasking, finishing procedure 115 Walter Shepard [ JPD 1968;19: 562-564]
116. Fluid Resin Technique Disadvantages • Noticeable shifting of prosthetic teeth during processing • Air entrapment • Poor bonding between denture base of operations and acrylic teeth • Technique sensitivity 116 Walter Shepard [ JPD 1968;nineteen: 562-564]
117. • Fluid denture resin processing in a rigid mold • Koblitz FF et al described a fluid resin processing technique using rigid, modified gypsum investment as replacement for hydrocolloid investment. • Advantages • Method requires no specialized equipment such as metal flasks or hydrocolloid conditioning apparatus • The technique eliminates the time consuming step of sorting and replacing artificial teeth in as hydrocolloid mold. 117[ JPD 1973; 30; 339-345 ]
118. 118
119. 119
120. Cocky Cured Heat Cured Heat is not necessary for polymerization Porosity is greater Has lower average molecular weight (not Strong) Higher residual monomer content Rheological properties - Shows greater distortion - More initial deformation - Increased creep and slow recovery Poor color stability Easy to flask Heat is necessary Porosity is less Higher molecular weight Lower residue monomer content - Shows less distortion - Less initial deformation - Less pitter-patter and quicker recovery Color stability is adept Difficult to deflask Increased charge per unit of monomer improvidence at higher temperature. 120
121. Light Activated Denture Base Resins • This material has been described as a composite having a matrix of urethane dimethacrylate and microfine silica • Visible light is the activator • Camphoroquinone serves as the initiator for polymerization • Supplied in sheets and rope forms and is packed in light proof pouches. 121
122. Light Activated Denture Base of operations Resins • Can be used equally repair cloth and every bit custom tray material. • Unmarried component denture base is supplied every bit sheet and rope form in light proof pouches. 122
123. • Technique – Teeth are bundled, and the denture base is molded on an authentic cast. – Subsequently the denture base is exposed to high intensity visible lite source for an appropriate period – Following polymerization, the denture is removed from the cast, finished and polished in a conventional manner. 123
124. Properties Of Denture Base Resins • METHYL METHACRYLATE  Methyl methacrylate is a transparent liquid at room temp.  Concrete properties -Molecular weight = 100 -Melting point = - 48 C -Boiling point = 100.eight C -Density = 0.945g/ml at xx C -Heat of polymerization=12.nine Kcal/mol 124
125. POLYMETHYL METHACRYLATE • Transparent resin, transmits light in UV range to a wavelength of 250 nm. • Hard resin knoop hardness no of 18 to 20. • Tensile forcefulness is 60 MPa • Density is 1.nineteen chiliad/cm cube. • Modulus of elasticity two.4 GPa(2400 MPa) 125
126. POLYMETHYL METHACRYLATE • It is chemically stable and softens at 1250C • Information technology can exist molded as a thermoplastic textile between 125oC and 200oC. • Depolarization takes place at approx. 450oC . • Absorbs water by imbibition • Non crystalline structure possess high internal energy. 126
127. Forcefulness • Resins are typically low in strength, even so they have adequate compressive and tensile strength for complete or partial denture applications. • Compressive strength- 75 Mpa • Tensile strength- 52 Mpa Affected by:- • Composition of the resin • Technique of processing • Degree of polymerization • H2o sorption • Subsequent environment of the denture 127
128. Hardness • Resins have low hardness. They can be easily scratched and abraded. • Heat cured resin- xviii-20 KHN • Self cured resin- 16-eighteen KHN 128
129. Modulus of elasticity • Resins take sufficient stiffness [ 2400MPa] for use in complete and partial dentures. Impact Force • Information technology is the measure of energy absorbed by a fabric when it is cleaved by a sudden blow. • Add-on of plasticizers increase the impact strength. 129
130. 130
131. Polymerization shrinkage • When MMA monomer is polymerized to form PMMA.. Results in 21% volumetric shrinkage. • To reduce this loftier % of shrinkage… polymer powder is supplied in prepolymerized beads class which accounts for just 7% of volumetric shrinkage. • Distributed uniformly to all surfaces, hence the adaptation of denture bases to underlying soft tissues is non significantly afflicted. Processing shrinkage Due to stresses induced during processing • 0.26% for self cure resin • 0.53% for estrus activated resin 131
132. 132
133. Denture Warpage • It is the deformity or change of shape of the denture which bear on the fit of the denture. • Stresses incorporated during processing. 133
134. Denture Warpage • Acquired past:- • Stress causes by curing shrinkage or uneven or rapid cooling. • Packing of resin in rubbery stage. • Improper flasking. • During polishing, a rise in temperature occurs. 134
135. Denture Warpage • Caused past:- • Immersion of the denture in hot h2o. • Recuring of the denture after addition of relining material, etc. 135
136. Porosity • May compromise concrete, artful and hygienic backdrop of candy dentures. 136
137. Porosity Internal Porosity: • Is in form of voids or bubbles within the mass of processed resin. Information technology is confined to thick portions of denture base. • Results from vaporization of unreacted monomer and depression molecular wt. polymers, 137
138. Porosity External Porosity: • Inadequate mixing of pulverisation liquid components. • Inhomogeneity of resin mass • Inadequate pressure or insufficient material • Air inclusions incorporated during mixing procedures. 138
139. Water Sorption • Absorption is primarily by diffusion mechanism. • Water molecules occupy positions between polymer chains forcing the polymer chains apart. • The introduction of water molecules in the polymerized mass produces two important effects • Acts as plasticizers • Information technology causes slight expansion of polymerized mass 139
140. Water Sorption • PMMA exhibits a water sorption value of 0.69mg/cm2 • Fortunately these changes are relatively minor and exercise not exert meaning effects on the fit or part of candy bases. 140
141. Crazing • Is formation of surface cracks on denture base of operations resin. • Due to -Stress relaxation -Solvent action east.g. Ethyl alcohol • Crazing in a transparent resin imparts a hazy or foggy advent. • These surface cracks predispose a denture resin to fracture. 141
142. Plaque Adhesion • An invitro study done on the adhesion and penetration of C. Albicans proved that adhesion of C. Albicans occur, but they cant penetrate the Denture Base of operations Resin. 142 A COMPARATIVE IN-VITRO STUDY ON THE ADHERENCE AND PENETRATION OF C. ALBICANS TO THREE DIFFERENT RESIN DENTURE Base SURFACE -Dr. Divyang Patel
143. Other Microorganisms • Streptococcus Oralis, Bacteroides gingivalis, B. Intermedius And S. Sanguis. • It was found, they adhere to rougher surface than those that are highly polished. 143
144. Solution for Plaque Adhesion • Chlorhexidine apparently tin can bind to acrylic surfaces for atleast 2 weeks. • Treating acrylic with Nystatin, followed by drying, produced similar results. 144
145. Resistance to Acids, Bases And Organic Solvents • Weak acids or bases = First-class • Serenity resistant to Organic Solvents • Soluble in aromatic hydrocarbons, ketones and esters. • Booze will cause crazing in Denture plastic. • Incorporating ethylene glycol dimethacrylate as a cantankerous linking agents significantly improves solvent resistance. 145
146. DENTURE CLEANSER 146 • Virtually immersion denture cleansers are constructive in the removal of mucin, stains, and loosely fastened food debris. • A solution consisting of 1 tsp of a hypochlorite such as Clorox, and 2 tsp of calgon in one-half glass has been recommended for occassional overnight immersion of plastic dentures.
147. DENTURE CLEANSER 147
148. Cytotoxicity of Denture Base of operations Acrylic Resins [ JPD 2003: xc; 190-195 ] • Rest monomer, resulting from incomplete conversion of monomers into polymer, has the potential to crusade – irritation, – inflammation, – and an allergic responses of oral mucosa. • Clinical signs and symptoms reported include – erythema, – erosion of oral mucosa, – burning sensation of mucosa and tongue. 148
149. Cytotoxicity of Denture Base Acrylic Resins [ JPD 2003: xc; 190-195 ] Effect of polymer : monomer ratio • More monomer added to the mixture, the greater amount of residual monomer and therefore more potential for cytotoxicity . Effect of storage time and water immersion • Sheridan et al reported that cytotoxic event of acrylic resins was greater in first 24 hours after polymerization and decreased with time. • Therefore information technology is recommended that dentist soak the resin prosthesis in water for atleast 24 hours before placing them in the patients mouth. 149
150. • Effects of polymerization cycle • Reduced corporeality of residue monomer when polymerization time extended was observed. • Auto polymerized resins exhibited college content of rest monomer than heat polymerized resins. 150
151. • Lamb et al observed that levels of residue monomer were higher for specimens polymerized at 200C as compared with those at 550C. • Therefore it is suggested that the Autopolymerized acrylic resins should be heat treated to decrease cytotoxic effects. 151
152. Occupational Hazard • Plastic dough should not exist manipulated excessively with bare hands. • The monomer is a good solvent for body oils and may pick upwards dirt from the hands, resulting in a non esthetic denture. • Monomer may likewise enter blood stream through the skin. 152 Restorative Dental Materials, Robert G. Craig & John M Powers, 11th edition
153. Recent Advances Loftier IMPACT RESISTANT ACRYLIC • Butadiene- styrene rubber is incorporated with copolymer of vinyl and hydroxyethyl monomer. • These materials are slightly stiffer twice the impact strength absorbs less water lower linear shrinkage. But are not entirely colour stable. 153
154. Recent Advances HIGH IMPACT RESISTANT ACRYLIC Phase inversion resulting in dispersion throughout the beads of tiny islands of prophylactic containing small inclusions of rubber/PMMA graft polymer. 154
155. Recent Advances RAPID Rut POLYMERIZED POLYMER • These are hybrid acrylics which have had the initiator formulated to allow for very rapid polymerization without virtually as much porosity. • The flasks are placed in humid water immediately after being packed. The water is so brought back to a eddy for twenty min to complete the curing cycle. • Fast, high temperature cure makes this material stiffer than conventional acrylic processing. • E.g. travelon 155
156. FIBER –REINFORCED POLYMER • Glass, carbon/graphite, aramid and ultrahigh molecular weight polyethylene have been used as fiber reinforcing agents. • Metallic wires similar graphite has minimal esthetic qualities. • Fibers are stronger than matrix polymer thus their inclusion strengthens the blended structure. • The reinforcing agent can exist in the form of unidirectional, directly fiber or multidirectional weaves. 156
157. Acrylic resins with improved thermal conductivity • Thermal electrical conductivity of PMMA is three times less than metals. • Thermal conductivity of denture base materials is found to have an important effect on gustatory sensitivity. • Thermal conductivity of acrylic based materials can be improved by introducing a more thermally conducting phase inside the insulating acrylic resin matrix. • E.g. Al2O3, porcelain whiskers JPD 1998: 20; 278- 157
158. BPS (Biofunctional Prosthetic Arrangement) • BPS is the arrangement designed to piece of work with the body in a biologically harmonious style, maximizing role, and giving comfort and natural appearance to the patient. 158
159. 159 Resorbed ridges Occlussal centric tray loaded with impression for recording initial vertical dimension Biofunctional prosthetic system impression trays
160. 160 Seize with teeth registration through Gnathometer G Secondary impression-making with zinc oxide eugenol by Wax-upwards trial for the patient
161. 161 Acrylized Denture
162. Flexible Denture • First introduced in 1956. • Merchandise proper name:- – Flexiplast – Valplast • Superpolyamides, which vest to nylon family unit, which inherent property of flexibility. • Flexibility depends on the thickness • Good memory 162
163. Flexible Denture Advantage • Skilful retentivity Disadvantage • Acrylic teeth do non bond chemically with flexible denture base of operations. 163
164. VALPLAST • Nylon like material • Almost unbreakable, pinkish colored like gum • Can be built quite sparse, can grade non only denture base but the clasp as well. • Valplast is a flexible denture base of operations resin that is platonic for partial dentures and unilateral restorations. 164
165. VALPLAST – • The resin is a biocompatible nylon thermoplastic ,it eliminates the business organization nigh acrylic allergies. • Quite hygienic. It is not possible for Valplast to absorb the remnants of food or other stains. And so there will be no aroma. 165
166. Conclusion 166
167. Determination 167
168. 168
169. 169
170. References • Kenneth j. Anusavice ; Phillips Science of dental material .Eleventh edition, Elsevier,2004. • Robert C. Craig John M. Powers, John C.Wataha ;Dental materials properties and manipulation,. Eleventh edition,2002. • Applied Dental Materials, 8th edition, John F McCabe & Angus W. G. Walls • Rudd and morrow; dental laboratory procedures: 1986 2nd edition • Vk subbarao ; notes on dental materials : 4th edition 170
171. • Basic Dental Materials – John J. Manappallil, 3rd edition • Walter Shepard : fluid resin technique; JPD 1968 (nineteen) 561- • Koblitz F.F et al: Fluid denture resin processing in a rigid mold JPD1973 (30) 339- • Dimensional accuracy of pour acrylic resin and conventional processing of cold cure resin JPD 1970 (24) 662- • Atwood et al: final report of the workshop on clinical requirements of ideal denture base material ; JPD 1968(twenty) 101-105 171
172. • EW Skinner; acrylic denture base of operations material their concrete properties and manipulation. JPD 1951 (1) 161- • Comparison of cocky curing and heat curing denture base resins JPD 1953 (three) 332- • FA Peyton; evaluation of dentures processed by dissimilar technique JPD 1963 (13) 269- • Cytotoxicity of denture base acrylic resin JPD 2003 (xc) 190- • Bernard Levin et al; use of microwave energy for processing acrylic resins JPD 1989 (61) 381- 172
173. • Robert EO; Comparison of accurateness between compression and injection molded complete denture JPD 1999 (82) 291- • Glossary of Prosthodontic Terms 8 • A comparative in-vitro study on the adherence and penetration of c. ALBICANS TO THREE Dissimilar RESIN DENTURE BASE SURFACE - Dr. Divyang patel 173
174. 174

The scope, requirements and procedures for evaluating denture base plastics are listed in ANSI/ADA Specification No. 12
The specification includes acrylic, vinyl and styrene polymers, or mixtures of any of these polymers equally well as copolymers.

2nd indicate. Retention of imitation teeth became more difficult equally the number of teeth diminished in the mouth and those that wore full set of dentures had to remove them before eating.

In ancient times, the most common fabric for fake teeth were animate being os or ivory , especially from elephants or hippopotamus.
Human teeth were also used, pulled from the dead or sold by poor people from their ain mouths.

NELSON GOODYEAR

Dimensional changes WhY:-
Thermal expansion during Heating in the vulcanizer
Contraction of 2 to four% by volume during addition of the sulphur to the rubber.

John Hyatt

Prior to 1940, vulcanite was most widely used denture based polymer
Highly cross linked natural rubber which was difficult to pigmen and tend to get unhygienic due to uptake of saliva

Whatever impurity present increases the length of this menstruation.
The higher the temperature, the shorter is the length of the induction menstruum.
ii processses are needed :- activation and initiation

fifty to 100 c temp BPO two gratis radicals (benzoyl peroxide)
Chemicall activated tertiary amine (activator) and BPO initiator
Calorie-free activated camphorquinone and organic amine (dimethylaminoethyamine) blueish to violet region (470 nm calorie-free wavelenght)

Light activated camphorquinone and organic amine (dimethylaminoethyamine) generate free radicals...blue to violet region (470 nm light wavelenght)
Chemically activated tertiary amine (activator) and BPO initiator

Energy sourceforms free radical which opens up double or triple bail in the monomer

Rapid addition of monomer molecules to gratis radicals – complimentary radical shifted to end of chain

Realigning of molecules leading to improver of monomer molecules

The active gratis radical of growing chain is transferred to another molecule (due east.g monomer or inactive polymer chain) and a new free radical for further growth is created. Termination occurs in the later on.

The active free radical of growing chain is transferred to some other molecule (e.g monomer or inactive polymer chain) and a new free radical for further growth is created. Termination occurs in the after.

The chain reaction tin can be terminated either by directly coupling of ii free radical bondage

Termination by exchange of hydrogen cantlet from one growing chain to another

Depletion of free radicals and formation of polymers

Small amount of ethyl acrylate may exist copolymerized with methyl methacrylate to alter flexibility.
Cake and graft polymers show improved affect force. In small amount, also modify the adhesive backdrop of resin and surface feature.

Crazing is germination of surface cracks on the denture base resin

short, fine fibers that divide from the surface of fabric or yarn, esp. during processing.

PG 636 CRAIG PMMA, BPO & DIISOBUTYLAZONITRILE, MERCURIC SULPHIDE, CADMIUM SULPHIDE FERRIC OXIDE OR CARBON Blackness,
DYES NOT USES, LEACH OUT OF PLASTIC. LIGHTENING THE Color
ZINC OR TITANIUM OXIDES---- GLASS FIBERS, Chaplet, ZIRCONIUM SILICATE
PLASTIZIER TO Increase THE BONDING AND WETTING OF THE INORGANIC PARTICLES (TRIETHOXYSILANE CROSS LINKING Agent)

3rd bespeak:- to stimulate the gum, some even comprise red fibers to indistinguishable blood vessels.

Nigh WIDELY USED RESINS FOR THE FABRICATION OF Consummate DENTURES.

Cross linking amanuensis Ethylene glycol dimethacrylate(v-fifteen%).they are added to avoid crack or craze produced by stresses during drying.
Inhibitor Hydroquinone (trace) to avoid premature polymerization and enhance shelf life.

GLYCOL DIMETHACRYLATE

Devoid of undercut

Shaping of the stone – bract or pocketknife

When mixed in proper proportions, the resultant mass passes through five singled-out stages.

When mixed in proper proportions, the resultant mass passes through five distinct stages.

The polymerization of denture base resin is exothermic and the amount of the heat evolved may affect the properties of the candy denture bases.

Following the completion of curing, the denture flasks should be cooled slowly to room temperature
Rapid cooling may outcome in warping of denture base considering of difference in thermal wrinkle of resin and investing stone.
Hence flasks should be removed from the water bath and demote cooled for thirty min.

Of considerable importance

If too much monomer is use:-

Resins tin can also exist polymerized by microwave energy

Resins can too be polymerized by microwave energy

700 W microwave oven

The material is supplied equally a gel in the form of a putty

Spru channels 7 mm
Vent channels iii mm

Chemic activators are used to induce polymerization

Chemical activators are used to induce polymerization

MOST WIDELY USED RESINS FOR THE FABRICATION OF Consummate DENTURES.

Virtually WIDELY USED RESINS FOR THE FABRICATION OF Consummate DENTURES.

Supplied in form of powder and liquid. Mixed according to manufacturer'due south instructions.

, 1. The cast with denture wax-up has been attached to the surface of the plastic base.Fig. 2. The sprues for the maxillary denture extend then that they are even with the inner step; of the plastic base.Fig. three. The sprues for the mandibular denture are attached to the about distal indicate 4 each heel area.

The stress at which fracture occurs is called the ultimate strength.
Compresive strength – the resistance of a material to breaking under compression.
Tensile forcefulness -the resistance of a material to breaking under tension.

Hardness is the resistance of a material to indentation.
The knoop hardness is obtained by measurement of the length of an indentation from an diamond indenter and computing the number of kilograms required to give an indentation of 1mm2.

It is the measure of stiffness of a textile. It is equal to the ratio of the stress to the strain.
It is the measure of energy absorbed by a material when it is cleaved by a sudden blow.

It is fortunate that many types of denture base of operations materials are available that will produce satisfactory dentures. The requirements may vary for dissimilar patients, and the process- ing facilities can dictate which cloth to apply. In that location are also significant differences between products in each category, and information technology is wise to cull materials that have passed ANSI/ADA Specification No. 12

Porosity may be
Internal
External

Absorption is primarily by diffusion mechanism.
PMMA absorbs relatively minor amounts of water when placed in aqueous environment.

PMMA absorbs relatively small amounts of water when placed in aqueous environs.

Alcohol not used for cleaning and storing dentures.

Cobalt chromium alloys not used

HIEA :- senility and parkinsonism patients
less probable to be cleaved if dropped.
Incorporated into beads

Prophylactic inversion stage

Gustatory :- concerned with tasting or the sense of sense of taste
a single crystal of a cloth in the form of a filament with no dislocations.

Low-density impression material (syringe Acc Gel) was syringed into the vestibular expanse and the occlusal centric tray was loaded with high-density hydrocolloid and inserted into the patient'southward mouth to become the initial vertical dimension [

http://valplastpartial.com/valplast-partial-cleaner.html
Why biocompatible, because no monomer

http://valplastpartial.com/valplast-fractional-cleaner.html
Why biocompatible, because no monomer

http://valplastpartial.com/valplast-partial-cleaner.html
Why biocompatible, because no monomer

Fatigue strength :-0 dentures are subjected to big amount of circadian stresses during mastication
Fatigue strength represents the number of cycles earlier failure at a sure stress.

Source: https://www.slideshare.net/soham911/denture-base-resin-61697101

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What Is Denture Repair-it Liquid Made Of

Denture Base Resin

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