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DENTURE LINING MATERIALS

By,Head of Department

Dr Khawaja Rashid HassanRawal college of Dentistry

Islamabad

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DENTURE LINING MATERIALS

In cases where fitting surfaces of acrylic dentures needs replacement to improve the fit of the denture.

Classified into 3 main groups1. Hard reline materials.2. Tissue conditioners.3. Soft lining materials.

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1. HARD RELINE MATERIALS

Chair side relining technique is used.

Divided into 2 types.Both types are categorized as

auto polymerizable resins.Both types polymerize easily at

mouth or room temperature.

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1. HARD RELINE MATERIALS Composition

TYPE 1

POWDER POLYMER BEADS POLYMETHYLMETHACRYLATE

INITIATOR BENZOYL PEROXIDE

PIGMENTS INORGANIC SALTS

LIQUID MONOMER METHYLMETHACRYLATE

PLASTICIZER Di-n-butylphthalate

CHEMICAL ACTIVATOR

TERTIARY AMINE

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1. HARD RELINE MATERIALS Composition

TYPE 2

POWDER POLYMER BEADS POLYETHYLMETHACRYLATE

INITIATOR BENZOYL PEROXIDE

PIGMENTS INORGANIC SALTS

LIQUID MONOMER BUTYLMETHACRYLATE

CHEMICAL ACTIVATOR TERTIATY AMINE

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1. HARD RELINE MATERIALS

MANIPULATION: Grinding away some of the hard

surface of acrylic base. Powder and liquid are mixed. Applied over the fitting surface of the

acrylic base. Seated into the patient’s mouth. Closed mouth technique is used. Not allowed to remain in the patient ‘s

mouth throughout setting.

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1. HARD RELINE MATERIALS

PROPERTIES:1. Direct contact with the oral tissues is a

disadvantage.2. Methyl methacrylate in the monomer may

cause allergic reaction.3. Low values of glass transition temperature

(Tg) in both type 1 and type 2 materials.4. May become porous due to air entrapment

during mixing.5. Operator has little control over the

thickness of the material.

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2. TISSUE CONDITIONERS

Soft denture liners. Applied to the fitting surface of the

denture. Provides cushion to the fitting

surface. Plastic flow continues for 24-36

hours after mixing. Several applications in denture

works.

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2. TISSUE CONDITIONERS

Often applied to the dentures of the patients undergone surgery.

In case of immediate dentures, Addition of the tooth into the denture base that needs to be extracted.

Can be used as functional impression material.

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2. TISSUE CONDITIONERS

COMPOSITION

POWDER

POLYMER BEADS

POLYETHYMETHACRYLATE

LIQUID

SOLVENT ETHYL ALCOHOL

PLASTICIZER BUTYLPHTHALYL BUTYLGLYCOLATE

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2. TISSUE CONDITIONERS

COMPOSITIONAmount of solvent and

plasticizer is very crucial.7.5% - 40% of liquid contains

alcohol.Powder may be pigmented or

unpigmented.

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2. TISSUE CONDITIONERS

MANIPULATION On mixing powder and liquid, physical

process occurs. Smaller polymeric beads get dissolved and

larger beads swell up on absorbing solvent. Final set material is gel-like. High methacrylate, ethyl methacrylate,

plasticizer and solvent gives softness. Normally denture and patient’s soft tissues

are inspected after 2-3 days.

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2. TISSUE CONDITIONERS

PROPERTIES: Initially very soft and Viscoelastic. Undergo permanent deformation under

even small load. Material do not remain permanently soft. Time taken for the material to become

hard and loose the cushioning effect varies from days to a couple of weeks.

Conditioner should be replaced after 2- 3 days till the tissue has healed properly.

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3. SOFT LINING MATERIALS

Can be sub divided intoa) Temporary soft lining

materials.b) Permanent soft lining

materials.

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3. SOFT LINING MATERIALS

TEMPORARY SOFT LINING MATERIALS:

Almost similar to tissue conditioners. Supplied as powder liquid formulation. Composition and manipulation same

as tissue conditioners. Retain their softness for longer

duration.( upto a month or two) Selection of denture cleanser is very

crucial for temporary soft liners.

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3. SOFT LINING MATERIALS

PERMANENT SOFT LINING MATERIALS:

Commonly used in patients that cannot tolerate a hard base.

In patients with thin mandibular mucosa.

These materials should remain permanently soft for the life time of the denture.

Elasticity of these materials is very important.

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3. SOFT LINING MATERIALS AVAILABLE MATERIALS:1. ACRYLIC:

Heat cure. Cold cure.

2. SILICONE: Heat cure. Cold cure.

Condensation. Addition.

3. POLYPHOSPHAZINE:

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3. SOFT LINING MATERIALS

Heat cure acrylic is in powder liquid formulation.

Powder consist of poly ethyl or poly butyl methacrylate.

Liquid consists of butyl methacrylate and plasticizer.

Dough is formed which is then heat treated.

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3. SOFT LINING MATERIALS Heat cure silicone is used in the same

way as heat cue acrylic. Presented in a single paste formulation. Paste consist of poly di methylsiloxane

polymer. The 2 cold cure silicone elastomers are

similar to the silicone elastomers used as impression materials.

Cold curing silicones are cured at room temperature.

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3. SOFT LINING MATERIALS

POLYPHOSPHAZINE: Supplied in sheet form. Polymerize by heat cure. Curing cycle can be,

74°C for 8 hours.OR

74 °C for 2½ hours followed by 100 °C for 30 minutes.

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3. SOFT LINING MATERIALS

PROPERTIES: All types are soft and give an adequate

cushioning effect. Cushioning effect depends upon the

thickness of material. 2-3 mm is sufficient for adequate cushioning

effect. Harden through loss of alcohol and leaching

of plasticizer. Adequate bond with the denture base. Denture cleansers effect the soft liners.

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.THANKYOU

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