Soft liners and tissue conditioners

complete presentation including all information on tissue conditioners and soft liners

1. DR. DHANANJAY D SHETH 1 ST YEAR MDS DEPARTMENT OF PROSTHODONTICS SOFT LINERS AND TISSUE CONDITIONERS

2. DEFINITION : Tissue conditioner: 1. a resilient denture liner resin placed into a removable prosthesis for a short duration to allow time for tissue healing ; 2 . used in functional removable relining procedures to evaluate denture function and patient acceptance prior to laboratory reline processing. Tissue conditioning: a procedure in prosthodontics usually performed by relining a removable complete denture, removable partial denture, or a maxillofacial prosthesis with a resilient resin and allowing a short duration of time for the patient’s soft tissue to heal.

3. Reline \re- lın ΄\ vt (1851): the procedures used to resurface the intaglio of a removable dental prosthesis with new base material , thus producing an accurate adaptation to the denture foundation area. Resilient denture liner/ soft liner : an interim (ethyl methacrylate with phthalate plasticizers ) or definitive (processed silicone) liner of the intaglio surface of a removable complete denture, removable partial denture, or intraoral maxillofacial prosthesis

4. TISSUE CONDITIONERS Dentures can apply excessive forces to the supporting tissues because of poor fit or occlusal errors. These loads may be localized or generalized and can cause accelerated bone resorption , inflammation, and hyperplasia . The latter soft tissue conditions must be treated before denture construction and can often be improved significantly by nonsurgical procedures. Rest for the denture-supporting tissues can be achieved by removal of the dentures from the mouth for an extended period or the use of temporary soft liners inside the old dentures. Both procedures allow deformed tissue of the residual ridges to return to normal form

5. Tissue abuse caused by improper occlusion can be corrected by ( 1) withholding the faulty dentures from the patient, ( 2) adjusting/correcting the occlusion and refitting the denture by means of a tissue conditioner, and ( 3) substituting properly made dentures once the denture-bearing tissues have recovered . This usually can be readily achieved by removing the dentures for 48 to 72 hours before the impressions are made for the construction of new dentures. Treatment with so-called “tissue treatment or conditioning materials”is usually employed . These temporary lining materials consist of a polymer powder and an aromatic ester ethanol mixture and are both elastic and plastic ..

6. Consequently they provide an interim cushioning stage and allow the tissues to recover their unstressed shape. Their softness is maintained for several days while the tissues recover, and they have been widely used in dentistry for many years.

7. They are generally manufactured as powder and liquid. The powder is mainly an acrylic resin . It is mixed with a somewhat oily liquid plasticizer ( generally an alcoholic solvent) in a proportion of 1.25 to 1.5 of powder to 1 of liquid.6-10 The result is the formation of a soft and elastic gel with a high percentage of flow under compression . Tissue conditioners maintain their optimum characteristics under conditions in the mouth for approximately 3 days. The material adheres to itself (when dry), to dry acrylic resin (without molecular union), and to dry skin .° These materials act as soft cushions that allow the deformed mucosa to push against them and gradually recover their normal form.

8. Once the lining has been placed in the denture, inserted, and removed, the tissue surface of the denture is examined. If the denture base shows through the tissue conditioner in some areas, it means that, at this point, an excessive amount of pressure is still being exerted either because of a faulty denture base or because of malocclusion. The pressure spots must be ground away, and a new lining must be placed to correct these errors. The patient must be instructed not to brush the tissue surface of the denture, but only to rinse it with water. He must use a soft-food diet and should remove the dentures at night if possible. The patient is asked to return in three days.

9. Soft Liners   Introduction Relining is a process of resurfacing of a denture with new base materials to make it fit more accurately. While rebasing is a process of replacing the entire denture base material with new material. Relining is indicated when there is resorption of the ridge and denture lack retention and stability. It is for refitting of the impression surface . Definitions Reline (1851): The procedure used to resurface the tissue side of a denture with new base material, thus producing an accurate adaptation to the denture foundation (GPT-7).

10. What is a soft liner? They are elastomer polymers used in the prevention of chronic soreness from denture and preservation of supporting structures. They are made resilient by addition of alcohol type plasticizers or by co- polymerisation with the monomer unit. The hydrophilic polymer is a mixture of polyethylene glycol with diacetins . Resilient Denture Base Liners: The indications for use of a resilient liner are: existence of thin, non-resilient mucosal coverage of the residual ridge, poor ridge morphology, persistent denture-sore mouth, and acquired or congenital oral defects.

11. Stoner (1962) stated that the rational for using a soft lining material is that part of the energy transferred from it to the denture aids in deforming the denture elastically and consequently reduces the direct load of mastication on the atrophied area. In addition, the soft lining procedures as equal amount of pressure over the bone of the ridge and thereby avoids resistance from the prominent spicules to a larger amount of applied force. Ortman and Ortman (1975) have described the ideal properties of a resilient liner and recommended that these liners serve merely as aids in solving the problems and not as the total solution. Materials and Brand name: Silicone rubber materials Flexibase Simpa Cardex-Stabon Molloplast -B

12. Primasoft Prolastic Silastic 382 Soft acrylic materials Coe-soft Soft Oryl Coe-Super Soft Palasiv 62 Soft Nobiltone Softic 49 Virina Verno soft Other materials Hydrocryl Soft Liner Cole polymers Natural rubber

13. GC RELINE SOFT DETAX MOLLOSIL PERMANENT SOFT LINER

14. GC SOFT LINER MAJESTIC DRUG RELINE-IT DENTURE RELINER

15. PERMA SOFT DENTURE RELINER REVIVER SILICON DENTURE RELINING MATERIAL

16. Materials available for use as resilient liners are natural rubber, soft acrylic materials, vinyls , and silicone rubbers. Natural rubber has only a limited service period because of deterioration, fouling, and poor dimensional stability. Plasticized resin materials are the largest group of resilient liners; they are either cold-cure or heat-cure systems, and frequently they depend on the addition of plasticizer for their resilience. A plasticizer eventually leaches out, leaving the material hard and often fissured, thereby promoting staining. Vinyls have short-comings similar to those of resins because they may harden in service gradually. Lower resistance to abrasion also is a problem and may contribute to the poor fit of dentures.

17. Silicone rubbers probably are closest to being the ideal material. Achieving a satisfactory bond strength between the silicone lining and denture base resin for a reasonable service life has been a problem. Use of newer bonding agents seems to have increased the service life. Although silicone rubber is a suitable medium for the growth of fungus, proper denture hygiene minimizes this problem . Silicone rubber materials: Having no natural adhesion to polymethyl methacrylate, silicone rubbers depend on an adhesive or a bonding agent, such as a silicone polymer in a volatile solvent, for adherence of the lining to the denture base. The molecules of the polymer penetrate the acrylic of the denture base and anchor in it after evaporation of the solvent. As the resilient lining material cures, it adheres to the denture base by cross-linkage with the silicone polymer.

18. temporary soft liners or Tissue Conditioners Tissue conditioners as temporary soft liners are materials whose useful function is very short, generally a matter of a few days. Kydd and Mandley (1967) stated that tissue lining materials permit wider dispersion of forces and hence, aid to decrease the force per unit area transmitted to the supporting tissues. Such soft liners could serve as an analog of the mucoperiosteum with its relatively low elastic modulus. Currently for practical purposes, denture base materials are made of rigid materials. The dentist must recognize that the prolonged contact of these bases with the underlying tissues is bound to elicit changes of the tissues. Mucosal health may be promoted by hygienic and therapeutic measures and tissue-conditioning techniques may be applied when appropriate.

19. Tissue conditioners are indicated to condition the abused tissue, whereas soft liners are indicated to give a cushioning effect to relieve and protect vulnerable tissues . Composition: Tissue conditioners are composed of polyethyl -methacrylate and a mixture of aromatic ester and ethyl alcohol. Tissue conditioners are available as three component systems. Polymer (Powder) Monomer (Liquid) Liquid plasticizer (Flow control) Butylphthalyl butylglycolate Other polymers used: Polymethyl methacrylate, Silicone rubber, Poly ‘n’ propyl-methacrylate, poly ‘n’ butyl methacrylate. A gel is formed when these materials are mixed, with the ethyl alcohol having a greater affinity for the polymer.

20. Ideal properties:- Flow under constant force Resilient at high rates of deformation Remain viscous for several days Have a high adhesion to aid retention to denture base. Permanent resiliency Dimensional stability Adherence to denture base Dimensional stability Adherence to denture base Color stability Biocompatibility Intertness to fungus and bacteria Absence of odor, taste, irritation, toxicity. Ease of processing and repair Wettability Slow fluid absorption Abrasion resistance

21. Long shelf life Economical Disadvantages:- Low cohesive strength Affected by cleaners Alcohol can sting inflamed mucosa   Advantages:- Rheological and viscoelastic properties almost ideal Can be applied chairside Dentures fit well Can record freeway space  

22. Indications: Ridge atrophy/ resorption Bruxers Surgery Contraindications: Relief areas Xerostomia Obturators to enhance retention Denture opposing natural dentition

23. Points to Remember:- They survive only few weeks in mouth – although some are so well formulated as to remain resilient and in place for many months. However, it is their viscoelastic properties that are important, specifically their ability to flow under mastication and occlusal forces, spreading the load on the mucosa evenly. When first mixed they flow easily recording such voids as means of free space. They soon becomes highly viscous. After than they respond to changes in shape of mucosa. In this way swollen mucosa traumatized by ill-fitting dentures can recover .

24. Uses of Tissue Conditioners: The major uses of these tissue conditioning materials include: Tissue treatment Temporary obturator Baseplate stabilization To diagnose the outcome of resilient liners Liners in surgical splints Trial denture base Functional impression material Adjuncts for Tissue Healing: The merit of using a tissue conditioner is that they prepare the selected oral structures to withstand all the stress from the prosthesis. Tissue conditioners are generally used to preserve the residual ridge. They are also used to heal irritated hyperemic tissues prior to denture fabrication.

25. Temporary Obturator : Tissue conditioners may be added as a temporary obturator over the existing complete or partial denture; this may be done directly in the mouth or indirectly after an impression of the surgical areas has been made . Stabilization of Baseplates and Surgical Splints or Stents: When undercuts are present on an edentulous cast, an acrylic temporary denture base cannot be used as it may get locked into the undercut and break the cast during removal. In these cases tissue conditioners of a stiffer consistency may be used to stabilize the record bases and prevent breakage of the cast.

26. Adjunct to an Impression or as a Final Impression Material: These materials are used when it is difficult to determine the extent of the denture base due to the presence of movable oral structures. These materials record the extensions of the denture in a dynamic form that will later help in preparing an impression tray for the final impression. Adjunct to Determine the Potential Benefits of a Treatment Modality: Sometimes patients with well-constructed dentures develop chronic soreness and find it difficult to wear the dentures comfortably. Tissue conditioners can be used to determine if this problem can be resolved with the use of a resilient liner.

27. Procedure for Applying Tissue Conditioners: The following steps should be considered while applying a tissue conditioner on a denture. Preparation of the dentures: The tissue part of the denture base, which crosses an undercut, should be reduced. The tissue surface of the denture, which covers the crest of the ridge, should be reduced by 1 mm. It should be remembered that the dentures should allow sufficient room for the placement of the tissue conditioner in order to promote the recovery of displaced and traumatized tissues. Mixing and Placement of the Tissue Conditioner:- Tissue conditioners are available as three component systems. Polymer (Powder) Monomer (Liquid) Liquid plasticizer (Flow control). The mixing ratio can be changed according to the consistency required.

28. A ratio of 1.25 parts of polymer, 1 part monomer an d0.5cc plasticizer is usually recommended. The plasticizer should be added to the monomer. The ingredients are mixed to form a gel, which is applied in sufficient thickness to the tissue surface of the denture. The denture is inserted and border movements are carried out to mould the setting material. This method is similar to functional relining. Care and Maintenance: Tissue conditioners should not be cleaned by scrubbing with a hard brush in order to prevent tearing of the material. The use of soft brush under running water is recommended. The greatest virtue of tissue conditioners is their versatility and ease of use. Their biggest flaw is that they are so easily misused. Their longevity against wear is very limited and they tend to harden and roughen within 4 to 8 weeks due to the loss of plasticizer. Hence, they require close observation.

29. Properties: Viscous properties, which allow excellent adaptation to the irritated denture-bearing mucosa over a period of several days. Elastic behavior, which cushions the cyclic forces of mastication and bruxism. It should not be cleansed by scrubbing with a hard bristle brush. Cleansed with soft bristle brush under cold running water. Soaking denture in cleanser is not recommended since they can adversely affect the physical properties of tissue conditioners and cause premature deterioration. Most of denture cleansers are acidic and are absorbed by tissue conditioners and retained even after rinsing with water, mild acid can later be released when it places denture in the mouth and can cause irritation.

30. Requirements of Resilient Denture Base Liners: The requirements of soft liners are as follows:- They should be of a biologically inert material that is compatible with the oral tissues and does not support bacterial or fungal growth. They should be resilient and capable of maintaining this characteristic. Dentists agree that the average period of satisfactory service for a denture is 7 years; however, patients that need this resilient lining have special problems that often require more frequent service. For them, a reasonable period of service expected from such a material may be 2 years. After curing, they should be dimensionally stable and insoluble in oral fluids to maintain proper tissue contact. They should be color stable throughout their useful life, resistant to staining, and impervious to odors.

31. Even though flexible, they should resist abrasion and thereby allow the practice of proper hygiene of the surface. On curing, they should maintain their bond to the denture base without damaging it. It should be relatively easy to work with them, including during fabrication of the lining and its subsequent adjustment. However it is not essential for the liner to be a chairside material.

32. Resilient Liner Materials: Hard reline material Tissue conditioners Soft lining material   Heat cured Lining Denture Bases: A silicone rubber liner can be added to a previously processed denture base as a reline procedure or, more conveniently, can be included in the process of initial fabrication of the denture base.

33. Reline Procedure : According to Rudd and Morrow. Denture with soft tissue-conditioner is ready to be flasked Stone-plaster mix is spatulated onto outer surface of denture so as to avoid trapping air and to assure filling interproximal spaces Denture is inverted into lower half of denture flask filled with Stone- plastermix . No. 320 grit wet or dry sandpaper is used to put smooth Finish on stone-plaster surface and to facilitate seperation Of halves of flask before removal of tissue conditioner.

34. When stone-plaster mix has reached its final set, thin coat of Seperating medium is painted on surface to act as seperator . Second half of flask has been placed in position. Upper half of flask is positioned, and flask is filled with water at Room temperature to wet surface of tissue conditioner and to Prevent air bubbles from clinging to material during second pour. Vacum spatulated mix of dental stone is vibrated carefully into Upper half of flask to complete flasking . After flask is filled, lid Is positioned. After stone of second pour of denture flask has reached its final set, Flask is immersed in hot water, 130F, for approx 5min for easy seperation And seperated .

35. After stone of second pour of denture flask has reached its final set, Flask is immersed in hot water, 130F, for approx 5min for easy seperation And seperated . Tissue conditioner is removed and resin denture base is roughened With carbide base Seperating medium is applied to all gypsum surfaces of both halves of flask to facilitate seperation after processing. Bonding agent is applied to all exposed surfaces of resin denture base. Putty-like soft liner is formed into roll and placed on denture base and cured

36. B ring the temperature of the water to 160 F (71 C) within 30 minutes, and maintain this temperature for 30 minutes. During the next 30 minutes bring the water to a boil, and then boil it for 2 hours. The total curing time is 3 ½ hours.

37. Initial Processing Procedure Flask denture in a Hanau flask in conventional manner. Boil out and apply tinfoil substitute to all gypsum surfaces of both halves of flask, and allow them to dry thoroughly (approximately 5 minutes). To control the thickness of the Molloplast -B liner, a silicone putty spacer is constructed on the master cast in the lower half of the flask. Mix putty following manufacturer’s directions and mold onto master cast maintaining at least a 3 mm thickness. When set, trim borders with scissors. Reduce excess thickness with a coarse stone mounted in a high-speed lathe. Trial pack high-impact denture base resin in flask with silicone putty spacer.

38. Place flask in cold water in a Hanau curing unit, and set curing cycle and temperatures according to manufacturer’s recommendations. Bench cool and open flask. Halves of the flask will separate easily, as soft spacer does not engage undercuts in master cast. Remove spacer and flatten resin borders with a carbide bur to provide a butt joint. Reapply tinfoil substitute to gypsum surfaces of master cast and lower half of flask. Coat all exposed surfaces of resin with bonding agent. Trial pack, process, and finish Molloplast -B liner.

39. Problem Probable cause Solution Subsurface voids during initial flasking stages Improper application of stone-plaster mix to surface of denture Carefully apply stone-plaster mix to assure filling interproximal areas and avoid trapping air Vacuum spatulate stone-plaster mix in mechanical spatulator Inadequate duplication of denture border rolls Improper flasking Flask so as to assure inclusion of border rolls of impression in top half of the flask Fully expose border rolls prior to final set of stone-plaster mix Problem Areas: Resilient denture base liners (silicone):

40. Adherence of tissue conditioner to stone surface Too much free liquid remaining in tissue conditioner Alter powder-liquid ratio Prolong wearing time of tissue conditioner until flasking Chalky, rough, pitited stone surface See above See above Voids in top half of flask Dry surface of tissue conditioner Wet surface of tissue conditioner with water before pouring second half of flask   Improper flasking Use mechanical vibration to avoid entrapment of air bubbles Use vacuum-mixed dental stone

41. Denture base visible through resilient liner on adjustment Resilient liner too thin Inadequate removal of denture base material Remove adequate amount of denture base material to assure resilient liner 2 to 3 mm thick prior to packing and processing Fracture of denture base during usage Weak denture base material Denture base material too thin Use high-impact resin Leave minimum of 3mm of denture base material over crest of ridge Separation of resilient liner from denture base material No bonding agent used All surfaces not coated with bonding agent Use bonding agent recommended by manufacturer Apply bonding agent thoroughly to all surfaces to be covered with resilient liner

42. Small yellowish plaques on resilient liner surface Yeast organisms Soak for 30 minutes in solution of 1½ oz of Zephiran and 8 oz of water; scrub well with mild soap and water

43. Problem Probable cause Solution Surface voids Improper application of tinfoil substitute Flush mold surface with boiling water to eliminate any traces of wax.   Packing in cold mold Warm mold under heat lamp Subsurface voids (bubbles) Packaging Precompress soft liner in specially prepared flask. Trial pack three times   Underpacking Trial pack three times   Rapid monomer volatilization Reduce temperature and increase time of initial stage of cure cycle (150 F, 6 hours) Completely cure resin against silicone putty spacer before packing and processing soft liner Problems associated with silicone rubber liners :

44. Summary Since 1942, dentistry has sought to find a resilient denture lining material that would exhibit ideal clinical and laboratory qualities. To date, silicone materials have been considered the material of choice.   Conclusion: The greatest virtue of tissue conditioners lies in their versatility and ease of use. Their biggest flow is that they are so easily misused. Because the conditioner-lined dentures provide immediate relief and comfort, there is a danger that the patient will wear them too long and so cause trauma to the supporting tissue – thereby producing the very situation that their use is intended to prevent or correct. Their longevity in wear is very limited. They harden and roughen within four to eight weeks because of loss of the plasticizer. This requires close observation of the patient by the dentist.

45. References : Prosthodontic Treatment for Edentulous Patients, 12 th edition, Zarb Bolender . Boucher’s Prosthodontic Treatment for Edentulous Patients, 10 th edition, Zarb , Bolender , Hickey, Carlson. Phillip’s Science of Dental Materials, 11st Edition, Annusavice . Restorative Dental Materials, 11 th Edition, Craig. Dental Lab Procedures – Fixed Partial Dentures, 2 nd edition, Vol.2, Roads, Rudd, Marrow. Essential of Complete Denture Prosthodontics, 2 nd edition, Sheldon Winkler. Diagnosis and Treatment Planning for Edentulous Patients, Lancy , Philadelphia, 1983. J Prosthet Dent 1978; 40 : 89-97. J Prosthet Dent 1978; 40 : 334-342. J Prosthet Dent 1978; 40 : 499-508. J Prosthet Dent 1980; 43 : 348-351. J Prosthet Dent 1991; 65 : 413-418.

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