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DENTURE Recliners in prosthodontic dentistry
- 1.
- 2. CONTENTS LONG TERMSOFT LINERS Available materials Indications Ideal requirements Plasticized acrylics Silicone liners Comparison of the two Visible light cured resin system HARD LINERS Chair side reliners 2
- 3. 3 TREATMENT PROCEDURES CLINICAL LABORATORY PRINCIPAL PITFALLS REVIEW OF LITERATURE CONCLUSION REFRENCES
- 4. 4 Long term softliners
- 5. 5 LONG TERM LINERS: LONGTERM LINERS: Also called as permanent soft liners Also called as permanent soft liners These liners can be used for 1 year or longer These liners can be used for 1 year or longer Increases patient tolerance for tissue pain associated Increases patient tolerance for tissue pain associated with hard resin denture base with hard resin denture base
- 6. Long term softliners Mainly used as therapeutic measure for pts who can’t tolerate stress induced by dentures. In pts with sharp, thin, heavily resorbed ridges or with severe bony undercuts. The liner permits wider dispersion of impact forces that are involved in functional & parafunctional movements 6
- 7. 7 Materials available aspermanent soft liners
- 8.
- 9. Plasticized acrylics Heat activated Chemically activated Silicone soft liners Heat activated Room temperature vulcanization 9
- 10. 10 Indications of permanentliner They are used to: Cushion sharp edged alveolar processes Cases of flabby ridge & insufficient adhesion Relieve pressure from pressure spots Dam the palatal vibrating line Support the healing process in implantology
- 11. Requirements of ideallong term soft liner. Biocompatible Simple to manipulate Good dimensional stability Low water sorption & water solubility Good wettability by saliva Permanent softness/viscoelasticity 11
- 12. 12 Adequate abrasionresistance & tear resistance Good bond to denture base Unaffected by aqueous environment & cleansers, Easy to clean Color stability & good esthetics Inhibition of colonization by fungi and other micro-organisms
- 13. Plasticized acrylics Heat activated Supplied as preformed sheets or powder/liquid form. Powder Higher methacrylate polymer (PEMA) Benzoyl peroxide as initiator. Liquid Ethyl /n-butyl/2-ethoxy ethylene methacrylate 13
- 14. Plasticized acrylics -Heat activated. E.g. : Lucitone 199 Soft Oryl Coe-super soft Virnia Verno soft Palasiv 62. 14
- 15. Plasticized acrylic -chemically activated Composition similar to heat activated resins but polymerized by peroxide-tertiary amine system. Used as chair side reliner 15
- 16. 16 Major drawback: Foulodour Tendency to debond from denture base Presence of free monomer cause mucosal irritations.
- 17. Advantage: High wearand abrasion resistance. Disadvantage: Biodegradation in oral environment leading to rough surface that promotes calculus and food accumulation, harbors m.o, color changes. 17
- 18. 18 Plasticized acrylics –Chemically activated E.g: Flexacryl soft Acron MC Immediate (Lang dent)
- 19. Silicone soft liners Perhaps the most successful materials for liner application have been silicones as they are not dependent on leachable plasticizers therefore retaining their elastic property for longer time Silicone liners are provided as heat activated & room temperature vulcanization 19
- 20. Silicone soft liners Heatactivated Supplied as one component system i.e. paste or gel consisting: Poly (dimethyl siloxane) Viscous liquid consisting of silica as filler Benzoyl peroxide as initiator Adhesives (silicone polymer dissolved in a solvent or alkyl-silane coupling agent) enhances bond between liner and acrylic denture base. 20
- 21. Silicone soft liners-Heat activated. E.g: Molloplast –B Flexibase Simpa Cardex – Stabbon Primasoft Prolastic Silastic 382.
- 22. Room temperature vulcanizedsilicone(RTV) RTV silicones on the other hand, use a condensation cross linking process catalyzed by an organo-tin compound Supplied as two component sysyem These materials achieve lower degree of cross linking than their heat activated counterpart compromises many attributes as permanent liner 22
- 23. 23 E.g. : GC reline-soft& extra soft. Luci-soft denture liner system. Silicone soft liners- Room temperature vulcanization
- 24. 24 Mollosil Mollosilplus Soft line(kerr dental)
- 25. Advantages: High resiliency andprolonged elasticity Inert to body fluids Odourless, tasteless, easily molded Good dimensional stability. Disadvantages: Intrinsic inability to bond with denture base resin Porous nature harbors micro-organisms. 25
- 26. PLASTICIZED ACRYLIC: PLASTICIZED ACRYLIC:SILICONE RUBBER: SILICONE RUBBER: Less resilient Less resilient Highly resilient Highly resilient Hardness by time(loss of Hardness by time(loss of plasticizer) plasticizer) Retains softness and elasticity Retains softness and elasticity Good durable bond with denture Good durable bond with denture base base Low bond strength to acrylic base Low bond strength to acrylic base More resistant to growth of More resistant to growth of candida albicans candida albicans More susceptible to growth of candida More susceptible to growth of candida albicans albicans Better abrasion resistance Better abrasion resistance Low abrasion resistance Low abrasion resistance Reasonable resistance to damage Reasonable resistance to damage by denture cleanser by denture cleanser Less resistant to damage by cleansers Less resistant to damage by cleansers Acceptable tear strength Acceptable tear strength Low tear strength Low tear strength 26
- 27. 27 Despite vastclinical benefits, both materials exhibit properties far short of fulfilling requirements of an ideal permanent liner This fact has limited their life expectancy to a maximum of 1 year.
- 28. Disadvantages of permanentsoft liner: Disadvantages of permanent soft liner: In In vinyl and acrylic resins vinyl and acrylic resins plasticizer gradually leaches out thus making the plasticizer gradually leaches out thus making the material hard and changing their colour material hard and changing their colour Silicone elastomers Silicone elastomers adhere with difficulty to acrylic resin base, become bleached, adhere with difficulty to acrylic resin base, become bleached, stain easily, changes in dimensions & can be affected by candida albicans stain easily, changes in dimensions & can be affected by candida albicans 28
- 29. Hydrophilic acrylicresins Hydrophilic acrylic resins are not sufficiently soft, become discoloured are not sufficiently soft, become discoloured and tear easily and tear easily Polyurethanes Polyurethanes require special processing equipment ,difficult to process require special processing equipment ,difficult to process and discolour rapidly and discolour rapidly Ethyl methacrylates Ethyl methacrylates harden with time harden with time 29
- 30. 30 Visible light curedresin system Triad material is similar to light-cured composites but uses an organic rather than inorganic filler. JPD 1986;56:497-500.
- 31. 31 E.g: Triad - DuaLine™Dual Cure Reline Material- combines the accuracy of self-cure and the strength and dimensional stability of light cure. Triad - Hi-Flow Reline Material Triad - Reline Material Triad - Resiline™ Reline Material
- 32. 32 Composition :matrix of urethane dimethacrylate & small amounts of micro fine silica (controls rheology) The filler → acrylic resin beads of varying sizes (forms part of an interpenetrating polymer network structure when cured) Camphoroquinones-amine photo initiator.
- 33. 33 The prepareddenture base should be wetted with heat-polymerizing monomer to cause the surface layer to swell for 2 to 4 minutes before the bonding agent was applied to the dry, swollen surface.
- 34. The bondingagent is to be polymerized 2 minutes in the air and 2 minutes in the curing unit.
- 35. 35 The VLCresin is adapted to the denture with care not to trap or incorporate air within the material.
- 36. 36 The relinematerial on the impression surface and denture borders is polymerized by directing the visible light (hand-held visible light source ) on the polished surface of the denture directly in the pts mouth.
- 37. 37 Excess materialtrimmed away Additional material added at PPS and border areas Cure in unit for 10 min.
- 38. Advantages Accuracy offit Color stability Ease of fabrication and manipulation Flows easily Sets in the mouth in minutes Dimensionally stable Methyl and Butyl Methacrylate monomer-free 38
- 39. 39 PROPERTIES OF SOFTLINERS
- 40. 40 Water sorption : when placed in water, plasticizers & other components may leach out while water is absorbed until equilibrium is achieved Absorbed water may have detrimental effect on adhesion of liners to acrylic denture base, particularly if diffusion rate is fast At 1st week, water sorption will be from .03 to .40 mg/cm2 A processed liner would have no soluble components & low water sorption.
- 41. Biocompatibility: short aswell as long term liners have significant amount of plasticizer that leach considerably Phthalate esters have caused epithelial changes in vitro Potential premalignant changes are cause of concern as the amount of plasticizer leaching out maybe bw 10 to 40 times more than environmental or food uptake 41
- 42.
- 43. Hard reline materials Auto polymerizing resins Used to provide chair side reline. 43
- 44. CHAIR SIDE RELINERS(HARDSHORT TERM LINER) These materials are used for relining resin dentures directly in the mouth They often contain low moleculer weight polymers,plasticizers or solvents to increase their fluidity while seating the denture Some of them generate enough heat to injure oral tissues According to ADA Sp.17,peak temp.reached during curing should not be more than 75 c. 44
- 45. 45 Their propertiesare inferior to laboratory processed acrylic resins. They have higher porosity and water sorption They tend to discolor, become foul smelling and may even separate from the denture base Thus these materials have many disadvantages & are therefore considered as short term materials.
- 46. Composition: Powder – Polymer (PMMA) Initiator(benzoyl peroxide) Pigments Liquid – Monomer (Methyl methacrylate) Plasticizer (Butyl phthalate) Chemical activator (tertiary amine) 46
- 47. E.g. : Ufigel hard(VOCO) GC reline hard (GC corp) 47
- 48. 48 Flexyacryl hard (Langdent) Kooliner (GC corp)
- 49. Manipulation: Powderand liquid mixed according manufacturers instructions Smear tissue with petroleum jelly Bonding agent applied to denture tissue surface 49
- 50. 50 Applied tothe fitting surface of denture when in fluid consistency. When rubbery taken out of mouth and bench cured Exothermic reaction so material taken out as soon as in rubbery stage
- 51. Problems: Porous due toair inclusions while mixing Dentist has little control over thickness of lining Usually a increase in palatal thickness observed. 51
- 52. HEAT CURED ACRYLICRESIN (HARD LINER) New resin is cured against the old denture by compression molding technique. A low curing tempreture is necessary for the relining process to avoid distortion of the denture 52
- 53. 53 DISADVANTAGES: There is atendency for it to wrap toward the relined side due to: 1)diffusion of the monomer from the reliner before curing,and 2)Processing shrinkage of the liner
- 54. CARE AND MAINTAINANCE: CAREAND MAINTAINANCE: Excellent oral and denture hygiene Excellent oral and denture hygiene Antimicrobial agents to minimize Antimicrobial agents to minimize fungal/microbial colonization of liners fungal/microbial colonization of liners Liner should be soaked daily for 15 minutes in a Liner should be soaked daily for 15 minutes in a benzalkonium chloride of 1:750 concentration benzalkonium chloride of 1:750 concentration Liner should be wiped with cotton under cold Liner should be wiped with cotton under cold water water 54
- 55.
- 56. 56 Treatment procedures ClinicalProcedures: Preliminary treatment Impression procedures Lab Procedures
- 57.
- 58. LAB PROCEDURES FOR RELINING (Ruddand Morrow) 58 Relining Articular method Relining jig method
- 59. Preliminary treatment (WINKLER) Tissuepreparations Denture preparations maxillary denture preparation mandibular denture preparation 59 JPD 1957;7:27-42
- 60. Tissue preparations Render tissuesin a healthy status Use of tissue conditioners for 1-2 weeks to improve the mucosal health Advice the patient not to wear dentures for 1-2 wks (Soft tissue hypertrophy resolves) 60
- 61. Excessive hypertrophictissue eliminated with surgical intervention Dentures should not be worn during sleep Dentures should not be worn for at least 2 to 3 days prior to final impression appointment Daily massage of the tissues helpful to stimulate blood supply. Instruct the pt to take arm saline gargle 61 JPD 1957;7:27- 42.
- 62. Denture preparations Maxillary denture Reduce the borders of approx 2mm below vestibular spaces and frenum attachments. 62
- 63. 63 Relieve thetissue side in all areas covering stress bearing mucosa This is to allow room for the material.
- 64. 64 Provide escape holes Incisivepapillae region Near ridge in molar area Mid palatine raphe region
- 65. Mandibular denture Relieveany over extensions Relieve tissue surface covering crest and slopes of ridge Provide escape holes only if there is pendulous or excessively displaceable tissue. 65
- 66. Reline techniques (Boucher) Staticimpression technique Closed mouth tech. Open mouth tech. Functional impression technique Chair side technique. 66
- 67. Handle themaxillary denture first, allow an adjustment period then proceed with mandibular denture. Reason Easier to stabilize mandibular denture against the maxillary denture. 67
- 68. Static impression technique Closed mouth technique Open mouth technique 68
- 69. Closed mouth reliningtechnique (Winkler) maxillary denture- technique A ,, B ,, C ,, D Some prefer using existing centric relation record other prefer making new record mandibular denture- technique E Several methods have been described dentures used as impression trays 69
- 70. Disadvantage: Tissues not recordedin rest position Pt can’t determine the degree of pressure needed If occlusal discrepancies are present,the impression will not be accurate In case of a premature tooth contact the pt will shift the mandible to a comfortable position thereby shifting the denture base. 70
- 71. Functional Impression technique Simple and practical Routinely used Tissue conditioners used as functional impression materials Excellent refit obtained. 71
- 72. Denture preparationsdone The borders should be adequately formed If inadequate mold with auto polymerizing resin since liners need proper support to prevent slumping liner placed inside the denture The lining material should flow evenly to cover the whole impression surface 72
- 73. If voidsare present fresh layer of liner material is added Excess material trimmed away with hot scalpel.
- 74. Check after2-3 days for denuded areas These are pressure spots, relieve and apply a fresh thin coat of tissue conditioner.
- 75. New tissueliners cannot be used for final impression because: Dental stone’s or materials own weight deforms the impression when in plastic stage. 75
- 76. 76 Chair side technique Chemically cured plasticized acrylics, RTV silicones, hard acrylics, VLC resins. Added to denture and allowed to set in mouth to provide instant reline.
- 77. Advantage: Pt neednot go without dentures Disadvantages: Materials produce chemical burn on mucosa Result was often porous with bad odour Color stability poor In case the denture was not positioned properly material cannot be removed easily to repeat the procedure. 77
- 78. Principal pitfalls ProblemsDue to Improper Diagnosis Improper Preparation of the Soft Tissues Displacement or Loss of Orientation Occlusal Discrepancies 78
- 79. 79 Problems Dueto Improper Diagnosis Relining when the lack of fit is NOT the only problem Attempting to increase the vertical dimension too much Relining for a loss of minor retention
- 80. Improper Preparationof the Soft Tissues Relining over abused or inflamed tissue results in rapid loss of retention So do not reline until all the abused tissue has been recovered . 80
- 81. Displacement orLoss of Orientation Using heavy biting pressure when making the impression may cause displacement of the denture This may be due to failure to position the denture properly during the impression procedure. 81
- 82. Occlusal Discrepancies Remountprocedures with new interocclusal record followed by selective grinding is to be done. 82
- 83.
- 84. 84 ON GOING RESEARCHIS ON : ON GOING RESEARCH IS ON : Improving strength Improving strength Permanent resiliency Permanent resiliency Improved adhesion to denture base Improved adhesion to denture base Ability to inhibit growth of Ability to inhibit growth of microbes microbes Chemical stability Chemical stability
- 85. A studyby Han-Kuang Tan was conducted to compare color, texture, and Shore A hardness of a resilient silicone denture liners with after treatment with perborate, persulfate, or hypochlorite- containing denture cleansers at 25°C or 55°C. results:. Roughened specimens treated at 55°C with perborate-containing cleansers exhibited significantly greater color loss than those treated with the persulfate-containing cleanser. With roughened surfaces, significantly greater hardness was found with some perborate- containing cleanser compared with a hypochlorite- containing cleanser after treatment at 25°C. 85
- 86. A studywas conducted by H. MURATA, T. HAMADA, HARSHINI, K. TOKI & H. NIKAWA to evaluate the effect of addition of ethyl alcohol on the gelation & viscoelastic properties of tissue conditioners and to compare the effect of ethyl alcohal with that of the powder/liquid (P/L) ratio & it was concluded that: Addition of greater amounts of ethyl alcohal produced the shorter gelation time and the larger flow after gelation. Conversely, although the use of a higher P/L ratio produced a shorter gelation time, this procedure leads to a smaller flow after gelation. The results suggested that the addition of ethyl alcohal to the liquids of tissue conditioners is an effective method for controlling gelation times and viscoelastic properties after gelation. 86
- 87. H. MURATA,M. KAWAMURA, T. HAMADA studied the dimensional stability of tissue conditioners which characterizes the ability of the materials to yield accurate functional impressions of oral mucosa. This study evaluated the linear dimensional changes with time of six tissue conditioners (COE Comfort, FITT, GC Soft-Liner, Hydro-Cast, SR-Ivoseal and Visco- Gel) 87
- 88. 88 The percentagechanges in dimension and weight in water storage were measured at 2 (baseline), 8 and 24 h, and 2, 4, 7, 14 and 21 days after specimen preparation. The results suggested that the period recommended for forming functional impressions would be 24 h after insertion in the mouth.
- 89. A studyby HAYAKAWA etal. to clinically evaluate fluoroethylene copolymer liners in comparison to acrylic & silicone liners suggested that: fluoroethylene copolymer liners exhibit lesser water absorption & higher bond strength as compared to silicone liners as well as plasticized acrylic liners 89
- 90. A studyby D.M. QUIN on two recent antifungal agents, miconazole & ketaconazole which were combined with tissue conditioners & tested in vitro: miconazole & ketaconazole were as effective as nystatin in completely inhibiting the growth of candida Ineffectiveness of amphotericin b when combined with tissue conditioners as antifungal was confirmed. 90
- 91. Conclusion Attention andcare in the construction of complete dentures can minimize adverse changes in the supporting tissues and in associated facial structures, but it cannot preclude them. Thus the need for “servicing” complete dentures to keep pace with the changing surrounding and supporting tissue is mandatory. 91
- 92. To Conclude… Theuse of resilient liners in the prevention & treatment of chronic tissue irritation from dentures is an excellent alternative to the use of hard resins. Wider applications will be found in the near future once the present shortcomings of the available material are overcomed. 92
- 93. References 1. Phillips’ scienceof dental materials: Kenneth J Anusavice:11th edition;saunders elsever,2003 2. Restorative dental materials: Craig & powers :12th edition,mosby,2006 3. Prosthodontic treatment for edentulous patients: Zarb Bolender : 12th edition;mosby;2004 4. Essentials of complete denture prosthodontics: Sheldon Winkler :2nd edition;saunders;1976 5. Textbook of complete dentures: Rahn & Heartwell; 5th edition;lea & febiger,1993 93
- 94. 6. Effect ofresilient liners in removable partial dentures on stress distribution; Aydinlik E, Akay HU;J prost dent 1980:44(1);17-20. 7. Soft liners of fluoroethylene copolymer & its clinical evaluation; Iwao Hayakawa, Makoto Kawae, Yoshiyuki Tsuji, Eiichi Masuhara;J prost dent 1984:mar;51(3);310-313 8. Effect of addition of ethyl alcohol on gelation and viscoelasticity of tissue conditioners ; Murata H, Hamada T, Harshini, Toki K, Nikawa H; Journal of Oral Rehabilitation 2001 28; 48–54 9. Effect of Denture Cleansers, Surface Finish, and Temperature on Molloplast B Resilient Liner Color, Hardness, and Texture; Tan H, Woo A, Kim S, Lamoureux M, Grace M,J Prosthod 2000:sep.9(3);148-155. 94
- 95. 10. Dimensional stabilityand weight changes of tissue conditioners; Murata H, Kawamura M, Hamada T, Saleh S, Kresnoadi U, Toki K; Journal of Oral Rehabilitation 2001,oct. 28(10); 918-923 11. Effectiveness of miconazole & ketaconazole combined with tissue conditioners in inhibiting the growth of ; Quinn DM;Journal of Oral Rehabilitation 1985:mar;12(2);177-182 95
- 96.